lxml NULL Pointer Dereference allows attackers to cause a denial of service
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.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | lxml | < 4.9.1 | 4.9.1 |
References
- https://huntr.dev/bounties/8264e74f-edda-4c40-9956-49de635105ba
- https://github.com/lxml/lxml/commit/86368e9cf70a0ad23cccd5ee32de847149af0c6f
- https://github.com/advisories/GHSA-wrxv-2j5q-m38w
- https://nvd.nist.gov/vuln/detail/CVE-2022-2309
- https://github.com/lxml/lxml
- https://github.com/lxml/lxml/blob/master/CHANGES.txt
- https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2022-230.yaml
- https://lists.debian.org/debian-lts-announce/2024/09/msg00021.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HGYC6L7ENH5VEGN3YWFBYMGKX6WNS7HZ
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/URHHSIBTPTALXMECRLAC2EVDNAFSR5NO
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HGYC6L7ENH5VEGN3YWFBYMGKX6WNS7HZ
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/URHHSIBTPTALXMECRLAC2EVDNAFSR5NO
- https://security.gentoo.org/glsa/202208-06
- https://security.netapp.com/advisory/ntap-20220915-0006
- CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Weakness (CWE)
CWE-476- Platform
- Python (PyPI)
- Package
lxml- Disclosed
- 05.07.2022
- Updated
- 11.10.2026 12:19
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2022-230 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-wrxv-2j5q-m38w - CC BY 4.0
Vulnerability history: lxml
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 7
- First → latest
- 05.2014 04.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 1
- Medium 6
Disclosures per year
- 2017: 0
- 2018: 1
- 2019: 0
- 2020: 1
- 2021: 2
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 1
earlier: 1
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lxml NULL Pointer Dereference allows attackers to cause a denial of service this entry
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