GHSA-WRXV-2J5Q-M38W

Vulnerability from github – Published: 2022-07-06 00:00 – Updated: 2025-11-04 19:36
VLAI?
Summary
lxml NULL Pointer Dereference allows attackers to cause a denial of service
Details

NULL Pointer Dereference allows attackers to cause a denial of service (or application crash). This only applies when lxml is used together with libxml2 2.9.10 through 2.9.14. libxml2 2.9.9 and earlier are not affected. It allows triggering crashes through forged input data, given a vulnerable code sequence in the application. The vulnerability is caused by the iterwalk function (also used by the canonicalize function). Such code shouldn't be in wide-spread use, given that parsing + iterwalk would usually be replaced with the more efficient iterparse function. However, an XML converter that serialises to C14N would also be vulnerable, for example, and there are legitimate use cases for this code sequence. If untrusted input is received (also remotely) and processed via iterwalk function, a crash can be triggered.

Severity ?
5.3 (Medium)
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
6.9 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "lxml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.9.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-2309"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-07-06T19:14:23Z",
    "nvd_published_at": "2022-07-05T10:15:00Z",
    "severity": "MODERATE"
  },
  "details": "NULL Pointer Dereference allows attackers to cause a denial of service (or application crash). This only applies when lxml is used together with libxml2 2.9.10 through 2.9.14. libxml2 2.9.9 and earlier are not affected. It allows triggering crashes through forged input data, given a vulnerable code sequence in the application. The vulnerability is caused by the iterwalk function (also used by the canonicalize function). Such code shouldn\u0027t be in wide-spread use, given that parsing + iterwalk would usually be replaced with the more efficient iterparse function. However, an XML converter that serialises to C14N would also be vulnerable, for example, and there are legitimate use cases for this code sequence. If untrusted input is received (also remotely) and processed via iterwalk function, a crash can be triggered.",
  "id": "GHSA-wrxv-2j5q-m38w",
  "modified": "2025-11-04T19:36:22Z",
  "published": "2022-07-06T00:00:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-2309"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/commit/86368e9cf70a0ad23cccd5ee32de847149af0c6f"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/advisories/GHSA-wrxv-2j5q-m38w"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/lxml/lxml"
    },
    {
      "type": "WEB",
      "url": "https://github.com/lxml/lxml/blob/master/CHANGES.txt"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2022-230.yaml"
    },
    {
      "type": "WEB",
      "url": "https://huntr.dev/bounties/8264e74f-edda-4c40-9956-49de635105ba"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/09/msg00021.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HGYC6L7ENH5VEGN3YWFBYMGKX6WNS7HZ"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/URHHSIBTPTALXMECRLAC2EVDNAFSR5NO"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HGYC6L7ENH5VEGN3YWFBYMGKX6WNS7HZ"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/URHHSIBTPTALXMECRLAC2EVDNAFSR5NO"
    },
    {
      "type": "WEB",
      "url": "https://security.gentoo.org/glsa/202208-06"
    },
    {
      "type": "WEB",
      "url": "https://security.netapp.com/advisory/ntap-20220915-0006"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "lxml NULL Pointer Dereference allows attackers to cause a denial of service"
}


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  • 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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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