CVE-2021-28957
An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
02 / AFFECTED SOFTWARE
Affected packages
83 explicit affected versions
95 explicit affected versions
146 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
An XSS vulnerability was discovered in the python `lxml` clean module versions before 4.6.3. When disabling `the safe_attrs_only` and `forms` arguments, the `Cleaner` class does not remove the `formaction` attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in `lxml` 4.6.3.
An XSS vulnerability was discovered in python-lxml's clean module versions before 4.6.3. When disabling the safe_attrs_only and forms arguments, the Cleaner class does not remove the formaction attribute allowing for JS to bypass the sanitizer. A remote attacker could exploit this flaw to run arbitrary JS code on users who interact with incorrectly sanitized HTML. This issue is patched in lxml 4.6.3.
05 / REFERENCES
Further evidence
- https://bugs.launchpad.net/lxml/+bug/1888153
- https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999
- https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270
- https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ/
- https://security.gentoo.org/glsa/202208-06
- https://security.netapp.com/advisory/ntap-20210521-0004/
- https://www.debian.org/security/2021/dsa-4880
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://github.com/advisories/GHSA-jq4v-f5q6-mjqq
- https://github.com/lxml/lxml
- https://github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d
- https://github.com/lxml/lxml/pull/316
- https://github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml
- https://lists.fedoraproject.org/archives/list/[email protected]/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45
- https://lists.fedoraproject.org/archives/list/[email protected]/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ
- https://nvd.nist.gov/vuln/detail/CVE-2021-28957
- https://pypi.org/project/lxml
- https://security.netapp.com/advisory/ntap-20210521-0004