Vulnerability Description
HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion. Support for the <template> element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumbo.xs was not updated to support it. The element was treated as a text-node, where strlen() over-reads the heap block that the pointer addresses. Any caller that runs parse() with the default format => 'string', or with format => 'tree', on input containing a <template> element serializes the over-read bytes into the returned result, disclosing bounded heap contents. format => 'callback' reaches a croak on the unhandled node type and is unaffected.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://bugs.debian.org/1104789
- https://github.com/bestpractical/HTML-Gumbo/commit/15c0598909d4a64f47ef0a1abc505
- https://metacpan.org/release/BPS/HTML-Gumbo-0.19/changes
- http://www.openwall.com/lists/oss-security/2026/07/01/7
FAQ
What is CVE-2025-15646?
CVE-2025-15646 is a vulnerability with a CVSS score of 9.8 (CRITICAL). HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion. Support for the <template> element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumb...
How severe is CVE-2025-15646?
CVE-2025-15646 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2025-15646?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.