UBUNTU-CVE-2026-8927 (CVE-2026-8927)
Vulnerability from osv_ubuntu – Published: 2026-06-24 14:00 – Updated: 2026-07-08 07:51 – Source website
VLAI
Details
When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against proxyA using Digest auth, a subsequent transfer routed through proxyB erroneously leaks the Proxy-Authorization: header intended solely for proxyA.
Severity
9.1 (Critical)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "curl",
"binary_version": "7.35.0-1ubuntu2.20+esm20"
},
{
"binary_name": "libcurl3",
"binary_version": "7.35.0-1ubuntu2.20+esm20"
},
{
"binary_name": "libcurl3-gnutls",
"binary_version": "7.35.0-1ubuntu2.20+esm20"
},
{
"binary_name": "libcurl3-nss",
"binary_version": "7.35.0-1ubuntu2.20+esm20"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:14.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@7.35.0-1ubuntu2.20+esm20?arch=source\u0026distro=esm-infra-legacy/trusty"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.35.0-1ubuntu2.20+esm20"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"7.32.0-1ubuntu1",
"7.33.0-1ubuntu1",
"7.34.0-1ubuntu1",
"7.35.0-1ubuntu1",
"7.35.0-1ubuntu2",
"7.35.0-1ubuntu2.1",
"7.35.0-1ubuntu2.2",
"7.35.0-1ubuntu2.3",
"7.35.0-1ubuntu2.5",
"7.35.0-1ubuntu2.6",
"7.35.0-1ubuntu2.7",
"7.35.0-1ubuntu2.8",
"7.35.0-1ubuntu2.9",
"7.35.0-1ubuntu2.10",
"7.35.0-1ubuntu2.11",
"7.35.0-1ubuntu2.12",
"7.35.0-1ubuntu2.13",
"7.35.0-1ubuntu2.14",
"7.35.0-1ubuntu2.15",
"7.35.0-1ubuntu2.16",
"7.35.0-1ubuntu2.17",
"7.35.0-1ubuntu2.19",
"7.35.0-1ubuntu2.20",
"7.35.0-1ubuntu2.20+esm2",
"7.35.0-1ubuntu2.20+esm3",
"7.35.0-1ubuntu2.20+esm4",
"7.35.0-1ubuntu2.20+esm5",
"7.35.0-1ubuntu2.20+esm6",
"7.35.0-1ubuntu2.20+esm7",
"7.35.0-1ubuntu2.20+esm8",
"7.35.0-1ubuntu2.20+esm9",
"7.35.0-1ubuntu2.20+esm10",
"7.35.0-1ubuntu2.20+esm11",
"7.35.0-1ubuntu2.20+esm12",
"7.35.0-1ubuntu2.20+esm13",
"7.35.0-1ubuntu2.20+esm14",
"7.35.0-1ubuntu2.20+esm15",
"7.35.0-1ubuntu2.20+esm16",
"7.35.0-1ubuntu2.20+esm17",
"7.35.0-1ubuntu2.20+esm18",
"7.35.0-1ubuntu2.20+esm19"
]
},
{
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "curl",
"binary_version": "7.47.0-1ubuntu2.19+esm16"
},
{
"binary_name": "libcurl3",
"binary_version": "7.47.0-1ubuntu2.19+esm16"
},
{
"binary_name": "libcurl3-gnutls",
"binary_version": "7.47.0-1ubuntu2.19+esm16"
},
{
"binary_name": "libcurl3-nss",
"binary_version": "7.47.0-1ubuntu2.19+esm16"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:16.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@7.47.0-1ubuntu2.19+esm16?arch=source\u0026distro=esm-infra-legacy/xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.47.0-1ubuntu2.19+esm16"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"7.43.0-1ubuntu2",
"7.45.0-1ubuntu1",
"7.46.0-1ubuntu1",
"7.47.0-1ubuntu1",
"7.47.0-1ubuntu2",
"7.47.0-1ubuntu2.1",
"7.47.0-1ubuntu2.2",
"7.47.0-1ubuntu2.3",
"7.47.0-1ubuntu2.4",
"7.47.0-1ubuntu2.5",
"7.47.0-1ubuntu2.6",
"7.47.0-1ubuntu2.7",
"7.47.0-1ubuntu2.8",
"7.47.0-1ubuntu2.9",
"7.47.0-1ubuntu2.11",
"7.47.0-1ubuntu2.12",
"7.47.0-1ubuntu2.13",
"7.47.0-1ubuntu2.14",
"7.47.0-1ubuntu2.15",
"7.47.0-1ubuntu2.16",
"7.47.0-1ubuntu2.18",
"7.47.0-1ubuntu2.19",
"7.47.0-1ubuntu2.19+esm1",
"7.47.0-1ubuntu2.19+esm2",
"7.47.0-1ubuntu2.19+esm3",
"7.47.0-1ubuntu2.19+esm4",
"7.47.0-1ubuntu2.19+esm5",
"7.47.0-1ubuntu2.19+esm6",
"7.47.0-1ubuntu2.19+esm7",
"7.47.0-1ubuntu2.19+esm8",
"7.47.0-1ubuntu2.19+esm9",
"7.47.0-1ubuntu2.19+esm10",
"7.47.0-1ubuntu2.19+esm11",
"7.47.0-1ubuntu2.19+esm12",
"7.47.0-1ubuntu2.19+esm13",
"7.47.0-1ubuntu2.19+esm15"
]
},
{
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "curl",
"binary_version": "7.58.0-2ubuntu3.24+esm9"
},
{
"binary_name": "libcurl3-gnutls",
"binary_version": "7.58.0-2ubuntu3.24+esm9"
},
{
"binary_name": "libcurl3-nss",
"binary_version": "7.58.0-2ubuntu3.24+esm9"
},
{
"binary_name": "libcurl4",
"binary_version": "7.58.0-2ubuntu3.24+esm9"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:18.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@7.58.0-2ubuntu3.24+esm9?arch=source\u0026distro=esm-infra/bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.58.0-2ubuntu3.24+esm9"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"7.55.1-1ubuntu2",
"7.55.1-1ubuntu2.1",
"7.57.0-1ubuntu1",
"7.58.0-2ubuntu1",
"7.58.0-2ubuntu2",
"7.58.0-2ubuntu3",
"7.58.0-2ubuntu3.1",
"7.58.0-2ubuntu3.2",
"7.58.0-2ubuntu3.3",
"7.58.0-2ubuntu3.5",
"7.58.0-2ubuntu3.6",
"7.58.0-2ubuntu3.7",
"7.58.0-2ubuntu3.8",
"7.58.0-2ubuntu3.9",
"7.58.0-2ubuntu3.10",
"7.58.0-2ubuntu3.12",
"7.58.0-2ubuntu3.13",
"7.58.0-2ubuntu3.14",
"7.58.0-2ubuntu3.15",
"7.58.0-2ubuntu3.16",
"7.58.0-2ubuntu3.17",
"7.58.0-2ubuntu3.18",
"7.58.0-2ubuntu3.19",
"7.58.0-2ubuntu3.20",
"7.58.0-2ubuntu3.21",
"7.58.0-2ubuntu3.22",
"7.58.0-2ubuntu3.23",
"7.58.0-2ubuntu3.24",
"7.58.0-2ubuntu3.24+esm1",
"7.58.0-2ubuntu3.24+esm2",
"7.58.0-2ubuntu3.24+esm3",
"7.58.0-2ubuntu3.24+esm4",
"7.58.0-2ubuntu3.24+esm5",
"7.58.0-2ubuntu3.24+esm7",
"7.58.0-2ubuntu3.24+esm8"
]
},
{
"ecosystem_specific": {
"availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
"binaries": [
{
"binary_name": "curl",
"binary_version": "7.68.0-1ubuntu2.25+esm4"
},
{
"binary_name": "libcurl3-gnutls",
"binary_version": "7.68.0-1ubuntu2.25+esm4"
},
{
"binary_name": "libcurl3-nss",
"binary_version": "7.68.0-1ubuntu2.25+esm4"
},
{
"binary_name": "libcurl4",
"binary_version": "7.68.0-1ubuntu2.25+esm4"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:20.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@7.68.0-1ubuntu2.25+esm4?arch=source\u0026distro=esm-infra/focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.68.0-1ubuntu2.25+esm4"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"7.65.3-1ubuntu3",
"7.65.3-1ubuntu4",
"7.66.0-1ubuntu1",
"7.67.0-2ubuntu1",
"7.68.0-1ubuntu1",
"7.68.0-1ubuntu2",
"7.68.0-1ubuntu2.1",
"7.68.0-1ubuntu2.2",
"7.68.0-1ubuntu2.4",
"7.68.0-1ubuntu2.5",
"7.68.0-1ubuntu2.6",
"7.68.0-1ubuntu2.7",
"7.68.0-1ubuntu2.10",
"7.68.0-1ubuntu2.11",
"7.68.0-1ubuntu2.12",
"7.68.0-1ubuntu2.13",
"7.68.0-1ubuntu2.14",
"7.68.0-1ubuntu2.15",
"7.68.0-1ubuntu2.16",
"7.68.0-1ubuntu2.18",
"7.68.0-1ubuntu2.19",
"7.68.0-1ubuntu2.20",
"7.68.0-1ubuntu2.21",
"7.68.0-1ubuntu2.22",
"7.68.0-1ubuntu2.23",
"7.68.0-1ubuntu2.24",
"7.68.0-1ubuntu2.25",
"7.68.0-1ubuntu2.25+esm2",
"7.68.0-1ubuntu2.25+esm3"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "curl",
"binary_version": "7.81.0-1ubuntu1.25"
},
{
"binary_name": "libcurl3-gnutls",
"binary_version": "7.81.0-1ubuntu1.25"
},
{
"binary_name": "libcurl3-nss",
"binary_version": "7.81.0-1ubuntu1.25"
},
{
"binary_name": "libcurl4",
"binary_version": "7.81.0-1ubuntu1.25"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@7.81.0-1ubuntu1.25?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.81.0-1ubuntu1.25"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"7.74.0-1.3ubuntu2",
"7.74.0-1.3ubuntu3",
"7.80.0-3",
"7.81.0-1",
"7.81.0-1ubuntu1.1",
"7.81.0-1ubuntu1.2",
"7.81.0-1ubuntu1.3",
"7.81.0-1ubuntu1.4",
"7.81.0-1ubuntu1.6",
"7.81.0-1ubuntu1.7",
"7.81.0-1ubuntu1.8",
"7.81.0-1ubuntu1.10",
"7.81.0-1ubuntu1.11",
"7.81.0-1ubuntu1.13",
"7.81.0-1ubuntu1.14",
"7.81.0-1ubuntu1.15",
"7.81.0-1ubuntu1.16",
"7.81.0-1ubuntu1.17",
"7.81.0-1ubuntu1.18",
"7.81.0-1ubuntu1.19",
"7.81.0-1ubuntu1.20",
"7.81.0-1ubuntu1.21",
"7.81.0-1ubuntu1.22",
"7.81.0-1ubuntu1.23",
"7.81.0-1ubuntu1.24"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "curl",
"binary_version": "8.5.0-2ubuntu10.10"
},
{
"binary_name": "libcurl3t64-gnutls",
"binary_version": "8.5.0-2ubuntu10.10"
},
{
"binary_name": "libcurl4t64",
"binary_version": "8.5.0-2ubuntu10.10"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@8.5.0-2ubuntu10.10?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "8.5.0-2ubuntu10.10"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"8.2.1-1ubuntu3",
"8.2.1-1ubuntu3.1",
"8.4.0-2ubuntu1",
"8.5.0-2ubuntu1",
"8.5.0-2ubuntu2",
"8.5.0-2ubuntu8",
"8.5.0-2ubuntu9",
"8.5.0-2ubuntu10",
"8.5.0-2ubuntu10.1",
"8.5.0-2ubuntu10.2",
"8.5.0-2ubuntu10.3",
"8.5.0-2ubuntu10.4",
"8.5.0-2ubuntu10.5",
"8.5.0-2ubuntu10.6",
"8.5.0-2ubuntu10.7",
"8.5.0-2ubuntu10.8",
"8.5.0-2ubuntu10.9"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "curl",
"binary_version": "8.14.1-2ubuntu1.4"
},
{
"binary_name": "libcurl3t64-gnutls",
"binary_version": "8.14.1-2ubuntu1.4"
},
{
"binary_name": "libcurl4t64",
"binary_version": "8.14.1-2ubuntu1.4"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@8.14.1-2ubuntu1.4?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "8.14.1-2ubuntu1.4"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"8.12.1-3ubuntu1",
"8.13.0-5ubuntu1",
"8.14.1-1ubuntu2",
"8.14.1-1ubuntu3",
"8.14.1-2ubuntu1",
"8.14.1-2ubuntu1.1",
"8.14.1-2ubuntu1.2",
"8.14.1-2ubuntu1.3"
]
},
{
"ecosystem_specific": {
"availability": "No subscription required",
"binaries": [
{
"binary_name": "curl",
"binary_version": "8.18.0-1ubuntu2.2"
},
{
"binary_name": "libcurl3t64-gnutls",
"binary_version": "8.18.0-1ubuntu2.2"
},
{
"binary_name": "libcurl4t64",
"binary_version": "8.18.0-1ubuntu2.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "curl",
"purl": "pkg:deb/ubuntu/curl@8.18.0-1ubuntu2.2?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "8.18.0-1ubuntu2.2"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"8.14.1-2ubuntu1",
"8.17.0-1ubuntu1",
"8.18.0-1ubuntu1",
"8.18.0-1ubuntu2",
"8.18.0-1ubuntu2.1"
]
}
],
"aliases": [],
"details": "When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.",
"id": "UBUNTU-CVE-2026-8927",
"modified": "2026-07-08T07:51:40Z",
"published": "2026-06-24T14:00:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-8927"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-8927"
},
{
"type": "REPORT",
"url": "https://curl.se/L7HzKXisfJ/CVE-2026-8927.md"
},
{
"type": "ADVISORY",
"url": "https://ubuntu.com/security/notices/USN-8487-1"
}
],
"related": [
"USN-8487-1"
],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-8927"
]
}
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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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