CVE-2021-28957
Published: August 31, 2023Last modified: August 31, 2023
Description
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 6.1 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | REQUIRED |
| Scope | CHANGED |
| Confidentiality | LOW |
| Integrity impact | LOW |
| Availability impact | NONE |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | py3-lxml | Not affected (4.9.3-r1) |
| Stream | py3-lxml | Not affected (4.9.3-r0) |
References
- 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://lists.fedoraproject.org/archives/list/[email protected]/message/3C2R44VDUY7FJVMAVRZ2WY7XYL4SVN45/
- https://lists.fedoraproject.org/archives/list/[email protected]/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