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PYSEC-2020-178
Vulnerability from pysec - Published: 2020-01-22 19:15 - Updated: 2020-01-30 17:07
VLAI
Details
Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.
Impacted products
| Name | purl | waitress | pkg:pypi/waitress |
|---|
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "waitress",
"purl": "pkg:pypi/waitress"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "575994cd42e83fd772a5f7ec98b2c56751bd3f65"
}
],
"repo": "https://github.com/Pylons/waitress",
"type": "GIT"
},
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.4.0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"0.1",
"0.2",
"0.3",
"0.4",
"0.5",
"0.6",
"0.6.1",
"0.7",
"0.8",
"0.8.1",
"0.8.2",
"0.8.3",
"0.8.4",
"0.8.5",
"0.8.6",
"0.8.7",
"0.8.8",
"0.8.9",
"0.8.10",
"0.8.11b0",
"0.9.0b0",
"0.9.0b1",
"0.9.0",
"1.0a1",
"1.0a2",
"1.0.0",
"1.0.1",
"1.0.2",
"1.1.0",
"1.2.0b1",
"1.2.0b2",
"1.2.0b3",
"1.2.0",
"1.2.1",
"1.3.0b0",
"1.3.0",
"1.3.1"
]
}
],
"aliases": [
"CVE-2019-16792",
"GHSA-4ppp-gpcr-7qf6",
"GHSA-j7j6-7hfx-5522"
],
"details": "Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.",
"id": "PYSEC-2020-178",
"modified": "2020-01-30T17:07:00Z",
"published": "2020-01-22T19:15:00Z",
"references": [
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "FIX",
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"type": "ADVISORY",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-j7j6-7hfx-5522"
}
]
}
BREW-BACKGROUNDREMOVER-C… (GHSA-4PPP-GPCR-7QF6)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:37 – Updated: 2026-09-09 23:43 – Source website
VLAI
Summary
HTTP Request Smuggling: Content-Length Sent Twice in Waitress
Details
Impact
Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally.
So a request with:
Content-Length: 10
Content-Length: 10
would get transformed to:
Content-Length: 10, 10
Which would Waitress would then internally set to Content-Lenght: 0.
Waitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
References
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "waitress",
"resource_purl": "pkg:pypi/waitress@3.0.2",
"upstream_fixed_in": "1.4.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "backgroundremover",
"purl": "pkg:brew/backgroundremover"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.4.5"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/waitress@3.0.2",
"name": "waitress",
"resource": "waitress",
"strategy": "registry",
"subject_version": "3.0.2"
}
]
},
"details": "### Impact\n\nWaitress would header fold a double `Content-Length` header and due to being unable to cast the now comma separated value to an integer would set the `Content-Length` to 0 internally.\n\nSo a request with:\n\n```\nContent-Length: 10\nContent-Length: 10\n```\n\nwould get transformed to:\n\n```\nContent-Length: 10, 10\n```\n\nWhich would Waitress would then internally set to `Content-Lenght: 0`.\n\nWaitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0027t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0027t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "BREW-backgroundremover-CVE-2019-16792",
"modified": "2026-09-09T23:43:06Z",
"published": "2026-08-13T16:37:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16792"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2020-178.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.7.3",
"summary": "HTTP Request Smuggling: Content-Length Sent Twice in Waitress",
"upstream": [
"GHSA-4ppp-gpcr-7qf6",
"CVE-2019-16792",
"GHSA-j7j6-7hfx-5522",
"PYSEC-2020-178"
]
}
BREW-ICLOUDPD-CVE-2019-16792 (GHSA-4PPP-GPCR-7QF6)
Vulnerability from osv_homebrew – Published: 2026-08-13 16:59 – Updated: 2026-09-10 00:11 – Source website
VLAI
Summary
HTTP Request Smuggling: Content-Length Sent Twice in Waitress
Details
Impact
Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally.
So a request with:
Content-Length: 10
Content-Length: 10
would get transformed to:
Content-Length: 10, 10
Which would Waitress would then internally set to Content-Lenght: 0.
Waitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
References
| URL | Type | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "waitress",
"resource_purl": "pkg:pypi/waitress@3.0.2",
"upstream_fixed_in": "1.4.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "icloudpd",
"purl": "pkg:brew/icloudpd"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.32.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/waitress@3.0.2",
"name": "waitress",
"resource": "waitress",
"strategy": "registry",
"subject_version": "3.0.2"
}
]
},
"details": "### Impact\n\nWaitress would header fold a double `Content-Length` header and due to being unable to cast the now comma separated value to an integer would set the `Content-Length` to 0 internally.\n\nSo a request with:\n\n```\nContent-Length: 10\nContent-Length: 10\n```\n\nwould get transformed to:\n\n```\nContent-Length: 10, 10\n```\n\nWhich would Waitress would then internally set to `Content-Lenght: 0`.\n\nWaitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0027t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0027t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "BREW-icloudpd-CVE-2019-16792",
"modified": "2026-09-10T00:11:17Z",
"published": "2026-08-13T16:59:03Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16792"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2020-178.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.7.3",
"summary": "HTTP Request Smuggling: Content-Length Sent Twice in Waitress",
"upstream": [
"GHSA-4ppp-gpcr-7qf6",
"CVE-2019-16792",
"GHSA-j7j6-7hfx-5522",
"PYSEC-2020-178"
]
}
BREW-MKTXP-CVE-2019-16792 (GHSA-4PPP-GPCR-7QF6)
Vulnerability from osv_homebrew – Published: 2026-08-13 17:14 – Updated: 2026-09-10 00:32 – Source website
VLAI
Summary
HTTP Request Smuggling: Content-Length Sent Twice in Waitress
Details
Impact
Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally.
So a request with:
Content-Length: 10
Content-Length: 10
would get transformed to:
Content-Length: 10, 10
Which would Waitress would then internally set to Content-Lenght: 0.
Waitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
References
| URL | Type | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
||||||||||||||||||||||||||
{
"affected": [
{
"ecosystem_specific": {
"fix": "bump",
"range_state": "fixed",
"resource": "waitress",
"resource_purl": "pkg:pypi/waitress@3.0.2",
"upstream_fixed_in": "1.4.0"
},
"package": {
"ecosystem": "Homebrew",
"name": "mktxp",
"purl": "pkg:brew/mktxp"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.2.19"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"database_specific": {
"confidence": "high",
"source": "matched",
"strategy": "registry",
"upstream_evidence": [
{
"ecosystem": "PyPI",
"key": "pkg:pypi/waitress@3.0.2",
"name": "waitress",
"resource": "waitress",
"strategy": "registry",
"subject_version": "3.0.2"
}
]
},
"details": "### Impact\n\nWaitress would header fold a double `Content-Length` header and due to being unable to cast the now comma separated value to an integer would set the `Content-Length` to 0 internally.\n\nSo a request with:\n\n```\nContent-Length: 10\nContent-Length: 10\n```\n\nwould get transformed to:\n\n```\nContent-Length: 10, 10\n```\n\nWhich would Waitress would then internally set to `Content-Lenght: 0`.\n\nWaitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0027t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0027t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "BREW-mktxp-CVE-2019-16792",
"modified": "2026-09-10T00:32:14Z",
"published": "2026-08-13T17:14:17Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16792"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2020-178.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.7.3",
"summary": "HTTP Request Smuggling: Content-Length Sent Twice in Waitress",
"upstream": [
"GHSA-4ppp-gpcr-7qf6",
"CVE-2019-16792",
"GHSA-j7j6-7hfx-5522",
"PYSEC-2020-178"
]
}
CVE-2019-16792 (GCVE-0-2019-16792)
Vulnerability from cvelistv5 – Published: 2020-01-22 18:30 – Updated: 2024-08-05 01:24
VLAI
EPSS
VEX
Title
HTTP Request Smuggling: Content-Length Sent Twice in Waitress
Summary
Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.
Severity
7.1 (High)
CWE
- CWE-444 - Inconsistent Interpretation of HTTP Requests ('HTTP Request Smuggling')
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://www.oracle.com/security-alerts/cpuapr2022.html | x_refsource_MISC |
| https://docs.pylonsproject.org/projects/waitress/… | x_refsource_MISC |
| https://github.com/Pylons/waitress/security/advis… | x_refsource_CONFIRM |
| https://github.com/Pylons/waitress/commit/575994c… | x_refsource_MISC |
| https://lists.debian.org/debian-lts-announce/2022… | mailing-listx_refsource_MLIST |
Impacted products
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-05T01:24:48.422Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"tags": [
"x_refsource_CONFIRM",
"x_transferred"
],
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"name": "[debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update",
"tags": [
"mailing-list",
"x_refsource_MLIST",
"x_transferred"
],
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
}
],
"title": "CVE Program Container"
}
],
"cna": {
"affected": [
{
"product": "Waitress",
"vendor": "Pylons",
"versions": [
{
"lessThanOrEqual": "1.3.1",
"status": "affected",
"version": "\u003c= 1.3.1",
"versionType": "custom"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0."
}
],
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N",
"version": "3.1"
}
}
],
"problemTypes": [
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"descriptions": [
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"cweId": "CWE-444",
"description": "CWE-444 Inconsistent Interpretation of HTTP Requests (\u0027HTTP Request Smuggling\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2022-05-12T23:06:12.000Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"name": "[debian-lts-announce] 20220512 [SECURITY] [DLA 3000-1] waitress security update",
"tags": [
"mailing-list",
"x_refsource_MLIST"
],
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
}
],
"source": {
"advisory": "GHSA-4ppp-gpcr-7qf6",
"discovery": "UNKNOWN"
},
"title": "HTTP Request Smuggling: Content-Length Sent Twice in Waitress",
"x_legacyV4Record": {
"CVE_data_meta": {
"ASSIGNER": "security-advisories@github.com",
"ID": "CVE-2019-16792",
"STATE": "PUBLIC",
"TITLE": "HTTP Request Smuggling: Content-Length Sent Twice in Waitress"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "Waitress",
"version": {
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"value": "Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0."
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},
"impact": {
"cvss": {
"attackComplexity": "HIGH",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 7.1,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
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{
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},
"source": {
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"dateReserved": "2019-09-24T00:00:00.000Z",
"dateUpdated": "2024-08-05T01:24:48.422Z",
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},
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}
GHSA-4PPP-GPCR-7QF6
Vulnerability from github – Published: 2019-12-20 23:04 – Updated: 2026-01-22 22:34
VLAI
Summary
HTTP Request Smuggling: Content-Length Sent Twice in Waitress
Details
Impact
Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally.
So a request with:
Content-Length: 10
Content-Length: 10
would get transformed to:
Content-Length: 10, 10
Which would Waitress would then internally set to Content-Lenght: 0.
Waitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.
Patches
This issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies.
The Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don't cause any changes in behavior.
Workarounds
Various reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn't use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).
Issues/more security issues:
- open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)
- email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "waitress"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2019-16792"
],
"database_specific": {
"cwe_ids": [
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2019-12-20T23:02:03Z",
"nvd_published_at": null,
"severity": "CRITICAL"
},
"details": "### Impact\n\nWaitress would header fold a double `Content-Length` header and due to being unable to cast the now comma separated value to an integer would set the `Content-Length` to 0 internally.\n\nSo a request with:\n\n```\nContent-Length: 10\nContent-Length: 10\n```\n\nwould get transformed to:\n\n```\nContent-Length: 10, 10\n```\n\nWhich would Waitress would then internally set to `Content-Lenght: 0`.\n\nWaitress would then treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining.\n\n### Patches\n\nThis issue is fixed in Waitress 1.4.0. This brings a range of changes to harden Waitress against potential HTTP request confusions, and may change the behaviour of Waitress behind non-conformist proxies. \n\nThe Pylons Project recommends upgrading as soon as possible, while validating that the changes in Waitress don\u0027t cause any changes in behavior.\n\n### Workarounds\n\nVarious reverse proxies may have protections against sending potentially bad HTTP requests to the backend, and or hardening against potential issues like this. If the reverse proxy doesn\u0027t use HTTP/1.1 for connecting to the backend issues are also somewhat mitigated, as HTTP pipelining does not exist in HTTP/1.0 and Waitress will close the connection after every single request (unless the Keep Alive header is explicitly sent... so this is not a fool proof security method).\n\n### Issues/more security issues:\n\n* open an issue at https://github.com/Pylons/waitress/issues (if not sensitive or security related)\n* email the Pylons Security mailing list: pylons-project-security@googlegroups.com (if security related)",
"id": "GHSA-4ppp-gpcr-7qf6",
"modified": "2026-01-22T22:34:11Z",
"published": "2019-12-20T23:04:35Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16792"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/waitress/PYSEC-2020-178.yaml"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.4.0",
"severity": [],
"summary": "HTTP Request Smuggling: Content-Length Sent Twice in Waitress"
}
GHSA-J7J6-7HFX-5522
Vulnerability from github – Published: 2022-05-24 17:07 – Updated: 2026-02-25 14:07
Withdrawn 2026-01-22
VLAI
Summary
Duplicate Advisory: Inconsistent Interpretation of HTTP Requests in Waitress
Details
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-4ppp-gpcr-7qf6. This link is maintained to preserve external references.
Original Description
Waitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.
Severity
7.5 (High)
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.3.1"
},
"package": {
"ecosystem": "PyPI",
"name": "waitress"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-444"
],
"github_reviewed": true,
"github_reviewed_at": "2022-06-27T16:10:41Z",
"nvd_published_at": "2020-01-22T19:15:00Z",
"severity": "HIGH"
},
"details": "## Duplicate Advisory\nThis advisory has been withdrawn because it is a duplicate of GHSA-4ppp-gpcr-7qf6. This link is maintained to preserve external references.\n\n## Original Description\nWaitress through version 1.3.1 allows request smuggling by sending the Content-Length header twice. Waitress would header fold a double Content-Length header and due to being unable to cast the now comma separated value to an integer would set the Content-Length to 0 internally. If two Content-Length headers are sent in a single request, Waitress would treat the request as having no body, thereby treating the body of the request as a new request in HTTP pipelining. This issue is fixed in Waitress 1.4.0.",
"id": "GHSA-j7j6-7hfx-5522",
"modified": "2026-02-25T14:07:30Z",
"published": "2022-05-24T17:07:06Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/security/advisories/GHSA-4ppp-gpcr-7qf6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-16792"
},
{
"type": "WEB",
"url": "https://github.com/Pylons/waitress/commit/575994cd42e83fd772a5f7ec98b2c56751bd3f65"
},
{
"type": "WEB",
"url": "https://docs.pylonsproject.org/projects/waitress/en/latest/#security-fixes"
},
{
"type": "PACKAGE",
"url": "https://github.com/Pylons/waitress"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2022/05/msg00011.html"
},
{
"type": "WEB",
"url": "https://www.oracle.com/security-alerts/cpuapr2022.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "Duplicate Advisory: Inconsistent Interpretation of HTTP Requests in Waitress",
"withdrawn": "2026-01-22T22:34:03Z"
}
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Trend slope:
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(linear fit over daily sighting counts)
Show additional events:
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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