CVE-2021-28957: lxml vulnerable to Cross-Site Scripting
(updated )
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.
References
- bugs.launchpad.net/lxml/+bug/1888153
- github.com/advisories/GHSA-jq4v-f5q6-mjqq
- github.com/lxml/lxml
- github.com/lxml/lxml/commit/2d01a1ba8984e0483ce6619b972832377f208a0d
- github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999
- github.com/lxml/lxml/pull/316
- github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270
- github.com/pypa/advisory-database/tree/main/vulns/lxml/PYSEC-2021-19.yaml
- lists.debian.org/debian-lts-announce/2021/03/msg00031.html
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XXN3QPWCTQVOGW4BMWV3AUUZZ4NRZNSQ
- nvd.nist.gov/vuln/detail/CVE-2021-28957
- pypi.org/project/lxml
- security.gentoo.org/glsa/202208-06
- security.netapp.com/advisory/ntap-20210521-0004
- www.debian.org/security/2021/dsa-4880
- www.oracle.com/security-alerts/cpuoct2021.html
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