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No exploitation reportedFix available

CVE-2022-2309

No exploitation reported by the sources we read.

  • Published2022-07-05
  • Fixed in4.9.1
  • WeaknessCWE-476

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2022-07-0510:15CVE publishedNVD

Versions per branch

NVD · OSV
Lxmlversion to verify
BranchAffectedFixed in
4.9< 4.9.14.9.1
Fedoraproject fedora
BranchAffectedFixed in
36.x= 36no fix published
37.x= 37no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • libxml2Ubuntu:22.04:LTSall versions · fixed in 2.9.13+dfsg-1ubuntu0.2
  • libxml2Ubuntu:20.04:LTSall versions · fixed in 2.9.10+dfsg-5ubuntu0.20.04.5
  • libxml2Ubuntu:18.04:LTSall versions · fixed in 2.9.4+dfsg1-6.1ubuntu1.8
  • libxml2TuxCare:AlmaLinux:9.6all versions · fixed in 2.9.13-12.el9_6.tuxcare.els4and 3 other packages
  • libxml2openSUSE:Tumbleweedall versions · fixed in 2.10.1-1.1
  • libxml2openEuler:20.03-LTS-SP4all versions · fixed in 2.9.10-40.oe2003sp4
  • libxml2openEuler:20.03-LTS-SP1all versions · fixed in 2.9.10-38.oe1
  • libxml2Mageia:8all versions · fixed in 2.9.10-7.7.mga8

59 more package ranges on OSV.dev

Vendor advisories

  • CVE-2022-2309 Red Hat Product Security13 products fixed · 2 known affected

    lxml: NULL Pointer Dereference in lxml

    python-lxml.src (inkscape:flatpak) as a component of Red Hat Enterprise Linux 9 · python3-lxml (inkscape:flatpak) as a component of Red Hat Enterprise Linux 9

  • RHSA-2022:8226 Red Hat Product Security13 products fixed

    Red Hat Security Advisory: python-lxml security update

Full record on NVD

Fix

  1. Update Lxml to 4.9.1
  2. Vendor fix Red Hat Product Security RHSA-2022:8226 · 13 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  3. No fix available, says the vendor Red Hat Product Security CVE-2022-2309 · 2 productsAffected

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • CNACVSS 3.05.3known since 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-476known since 2026-10-23
  • FIRST EPSSEPSS score2.4 %2026-11-09
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryMODERATE2022-07-06

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2022-07-05
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-wrxv-2j5q-m38w

Frequently asked questions

What is CVE-2022-2309?

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.

Is CVE-2022-2309 actively exploited?

Active exploitation of CVE-2022-2309 has not been confirmed. Its EPSS score was 2.4% on 2026-11-09, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2022-2309?

CVE-2022-2309 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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