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Security Advisories: GSA_kwCzR0hTQS01amZ3LWdxNjQtcTQ1Zs4ABBj9
HTML Cleaner allows crafted scripts in special contexts like svg or math to pass through
Impact
The HTML Parser in lxml does not properly handle context-switching for special HTML tags such as <svg>
, <math>
and <noscript>
. This behavior deviates from how web browsers parse and interpret such tags. Specifically, content in CSS comments is ignored by lxml_html_clean but may be interpreted differently by web browsers, enabling malicious scripts to bypass the cleaning process. This vulnerability could lead to Cross-Site Scripting (XSS) attacks, compromising the security of users relying on lxml_html_clean in default configuration for sanitizing untrusted HTML content.
Patches
Users employing the HTML cleaner in a security-sensitive context should upgrade to lxml 0.4.0, which addresses this issue.
Workarounds
As a temporary mitigation, users can configure lxml_html_clean with the following settings to prevent the exploitation of this vulnerability:
remove_tags
: Specify tags to remove - their content is moved to their parents' tags.kill_tags
: Specify tags to be removed completely.allow_tags
: Restrict the set of permissible tags, excluding context-switching tags like<svg>
,<math>
and<noscript>
.
References
- https://github.com/fedora-python/lxml_html_clean/pull/19
- https://github.com/fedora-python/lxml_html_clean/pull/19/commits/c5d816f86eb3707d72a8ecf5f3823e0daa1b3808
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS01amZ3LWdxNjQtcTQ1Zs4ABBj9
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: 21 days ago
Updated: 21 days ago
CVSS Score: 7.7
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:H
EPSS Percentage: 0.00045
EPSS Percentile: 0.17556
Identifiers: GHSA-5jfw-gq64-q45f, CVE-2024-52595
References:
- https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-5jfw-gq64-q45f
- https://github.com/fedora-python/lxml_html_clean/pull/19
- https://github.com/fedora-python/lxml_html_clean/commit/c5d816f86eb3707d72a8ecf5f3823e0daa1b3808
- https://nvd.nist.gov/vuln/detail/CVE-2024-52595
- https://github.com/advisories/GHSA-5jfw-gq64-q45f
Blast Radius: 1.0
Affected Packages
pypi:lxml-html-clean
Dependent packages: 26Dependent repositories: 0
Downloads: 3,342,844 last month
Affected Version Ranges: < 0.4.0
Fixed in: 0.4.0
All affected versions: 0.1.0, 0.1.1, 0.2.0, 0.2.1, 0.2.2, 0.3.0, 0.3.1
All unaffected versions: 0.4.0, 0.4.1