lxml: javascript: URL bypass in Cleaner via xlink:href
Summary
| CVE | CVE-2026-49825 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-08-20 15:17:30 UTC |
| Updated | 2026-08-21 17:16:31 UTC |
| Description | lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.1, link attributes in ``lxml.html.defs.link_attrs`` were missing ``xlink:href``, which can be used for URL bypass attacks in embedded SVG/MathML/etc. content. This vulnerability was fixed in lxml 6.1.1 and lxml_html_clean 0.4.5. |
Risk And Classification
Primary CVSS: v3.1 8.2 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
EPSS: 0.002400000 probability, percentile 0.153660000 (date 2026-08-21)
Problem Types: CWE-79 | CWE-184 | CWE-79 CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') | CWE-184 CWE-184: Incomplete List of Disallowed Inputs
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N |
| 3.1 | CNA | DECLARED | 8.2 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
RequiredScope
ChangedConfidentiality
HighIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Lxml | Lxml | affected < 6.1.1 | Not specified |
| CNA | Fedora-python | Lxml Html Clean | affected < 0.4.5 | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/fedora-python/lxml_html_clean/releases/tag/0.4.5 | [email protected] | github.com | |
| github.com/lxml/lxml/releases/tag/lxml-6.1.1 | [email protected] | github.com | |
| github.com/lxml/lxml/commit/5927a6d5e851845140975d99b65461e255caaab0 | [email protected] | github.com | |
| github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-4jhm-j... | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | github.com | |
| github.com/fedora-python/lxml_html_clean/commit/322357ac61c6cf80fcbaba53... | [email protected] | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.