CVE-2021-28957
MEDIUM 6.1
At a glance
- Source
- NVD
- EPSS
- EPSS 4.04 % · percentile 91 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- mitre
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-79 — Improper Neutralization of Input During Web Page Generation
References
- https://bugs.launchpad.net/lxml/+bug/1888153
- https://github.com/lxml/lxml/pull/316/commits/10ec1b4e9f93713513a3264ed6158af22492f270
- https://lists.debian.org/debian-lts-announce/2021/03/msg00031.html
- https://www.debian.org/security/2021/dsa-4880
- 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://www.oracle.com/security-alerts/cpuoct2021.html
- https://github.com/lxml/lxml/commit/a5f9cb52079dc57477c460dbe6ba0f775e14a999
- https://security.netapp.com/advisory/ntap-20210521-0004/
- https://security.gentoo.org/glsa/202208-06
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | CISA-ADP |
| CVSS 3.1 | MEDIUM 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | MEDIUM 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 2.0 | MEDIUM 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N | NVD · nvd@nist.gov (Primary) |
Advisories
- GHSA-jq4v-f5q6-mjqq — lxml vulnerable to Cross-Site Scripting
- PYSEC-2021-19 — 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 cla
European references
- ENISA EUVD · EUVD-2021-0116
- GCVE · GCVE-0-2021-28957
CERT-FR advisories
- CERTFR-2026-AVI-0395 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2024-AVI-0297 — Multiples vulnérabilités dans Juniper · cert.ssi.gouv.fr
- CERTFR-2024-AVI-0262 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2023-AVI-0142 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:lxml:lxml:*:*:*:*:*:*:*:*< 4.6.3cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*cpe:2.3:a:netapp:snapcenter:-:*:*:*:*:*:*:*cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| affected n/a |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |