What’s Vulnerable › Vulnerabilities

CVE-2025-15646: HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-01 · updated 2026-10-06
• Weakness: CWE-125

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.

Affected products

• BPS HTML::Gumbo: before 0.19 — fixed in 0.19

How to fix

Upgrade to a fixed version: BPS HTML::Gumbo 0.19. Check the vendor advisory for mitigations.

References

• https://bugs.debian.org/1104789
• https://github.com/bestpractical/HTML-Gumbo/commit/15c0598909d4a64f47ef0a1abc5051f4e113c186.patch
• https://metacpan.org/release/BPS/HTML-Gumbo-0.19/changes
• http://www.openwall.com/lists/oss-security/2026/07/01/7

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