PYSEC-2026-1055

Vulnerability from pysec - Published: 2026-07-07 10:17 - Updated: 2026-07-07 11:31
VLAI
Details

When the host header does not match a configured host, twisted.web.vhost.NameVirtualHost will return a NoResource resource which renders the Host header unescaped into the 404 response allowing HTML and script injection.

Example configuration:

from twisted.web.server import Site
from twisted.web.vhost import NameVirtualHost
from twisted.internet import reactor

resource = NameVirtualHost()
site = Site(resource)
reactor.listenTCP(8080, site)
reactor.run()

Output:

❯ curl -H"Host:<h1>HELLO THERE</h1>" http://localhost:8080/

<html>
  <head><title>404 - No Such Resource</title></head>
  <body>
    <h1>No Such Resource</h1>
    <p>host b'<h1>hello there</h1>' not in vhost map</p>
  </body>
</html>

This vulnerability was introduced in f49041bb67792506d85aeda9cf6157e92f8048f4 and first appeared in the 0.9.4 release.

Severity
5.4 (Medium)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.1 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Impacted products
Name purl
twisted pkg:pypi/twisted
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "twisted",
        "purl": "pkg:pypi/twisted"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.9.4"
            },
            {
              "fixed": "22.10.0rc1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.0.1",
        "1.0.3",
        "1.0.4",
        "1.0.5",
        "1.0.6",
        "1.0.7",
        "1.1.0",
        "1.1.1",
        "1.2.0",
        "10.0.0",
        "10.1.0",
        "10.2.0",
        "11.0.0",
        "11.1.0",
        "12.0.0",
        "12.1.0",
        "12.2.0",
        "12.3.0",
        "13.0.0",
        "13.1.0",
        "13.2.0",
        "14.0.0",
        "14.0.1",
        "14.0.2",
        "15.0.0",
        "15.1.0",
        "15.2.0",
        "15.2.1",
        "15.3.0",
        "15.4.0",
        "15.5.0",
        "16.0.0",
        "16.1.0",
        "16.1.1",
        "16.2.0",
        "16.3.0",
        "16.3.1",
        "16.3.2",
        "16.4.0",
        "16.4.1",
        "16.5.0",
        "16.5.0rc1",
        "16.5.0rc2",
        "16.6.0",
        "16.6.0rc1",
        "16.7.0rc1",
        "16.7.0rc2",
        "17.1.0",
        "17.1.0rc1",
        "17.5.0",
        "17.9.0",
        "17.9.0rc1",
        "18.4.0",
        "18.4.0rc1",
        "18.7.0",
        "18.7.0rc1",
        "18.7.0rc2",
        "18.9.0",
        "18.9.0rc1",
        "19.10.0",
        "19.10.0rc1",
        "19.2.0",
        "19.2.0rc1",
        "19.2.0rc2",
        "19.2.1",
        "19.7.0",
        "19.7.0rc1",
        "2.1.0",
        "2.4.0",
        "2.5.0",
        "20.3.0",
        "20.3.0rc1",
        "21.2.0",
        "21.2.0rc1",
        "21.7.0",
        "21.7.0rc1",
        "21.7.0rc2",
        "21.7.0rc3",
        "22.1.0",
        "22.1.0rc1",
        "22.2.0",
        "22.2.0rc1",
        "22.4.0",
        "22.4.0rc1",
        "22.8.0",
        "22.8.0rc1",
        "8.0.0",
        "8.0.1",
        "8.1.0",
        "8.2.0",
        "9.0.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2022-39348",
    "GHSA-vg46-2rrj-3647"
  ],
  "details": "When the host header does not match a configured host, `twisted.web.vhost.NameVirtualHost` will return a `NoResource` resource which renders the Host header unescaped into the 404 response allowing HTML and script injection.\n\nExample configuration:\n```python\nfrom twisted.web.server import Site\nfrom twisted.web.vhost import NameVirtualHost\nfrom twisted.internet import reactor\n\nresource = NameVirtualHost()\nsite = Site(resource)\nreactor.listenTCP(8080, site)\nreactor.run()\n```\nOutput:\n```\n\u276f curl -H\"Host:\u003ch1\u003eHELLO THERE\u003c/h1\u003e\" http://localhost:8080/\n\n\u003chtml\u003e\n  \u003chead\u003e\u003ctitle\u003e404 - No Such Resource\u003c/title\u003e\u003c/head\u003e\n  \u003cbody\u003e\n    \u003ch1\u003eNo Such Resource\u003c/h1\u003e\n    \u003cp\u003ehost b\u0027\u003ch1\u003ehello there\u003c/h1\u003e\u0027 not in vhost map\u003c/p\u003e\n  \u003c/body\u003e\n\u003c/html\u003e\n```\n\nThis vulnerability was introduced in f49041bb67792506d85aeda9cf6157e92f8048f4 and first appeared in the 0.9.4 release.",
  "id": "PYSEC-2026-1055",
  "modified": "2026-07-07T11:31:24.020421Z",
  "published": "2026-07-07T10:17:22.852562Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/twisted/twisted/security/advisories/GHSA-vg46-2rrj-3647"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-39348"
    },
    {
      "type": "WEB",
      "url": "https://github.com/twisted/twisted/commit/f2f5e81c03f14e253e85fe457e646130780db40b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/twisted/twisted/commit/f49041bb67792506d85aeda9cf6157e92f8048f4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/twisted/twisted"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00038.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/11/msg00028.html"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202301-02"
    },
    {
      "type": "PACKAGE",
      "url": "https://pypi.org/project/twisted"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-vg46-2rrj-3647"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Twisted vulnerable to NameVirtualHost Host header injection"
}


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