Heap-memory disclosure via template-node type confusion
Published Jul 1, 2026 · Updated Jul 1, 2026
Out-of-bounds read in HTML::Gumbo before 0.19 allows attackers to disclose bounded heap contents through crafted template elements. The walk_tree function in lib/HTML/Gumbo.xs routes GUMBO_NODE_TEMPLATE through the text-node branch, causing strlen() to read beyond the heap object. Parsing attacker-controlled HTML in the default string format or tree format returns the over-read bytes; callback format aborts on the node type and is unaffected.
Summary
What happened
Out-of-bounds read in HTML::Gumbo before 0.19 allows attackers to disclose bounded heap contents through crafted template elements. The walk_tree function in lib/HTML/Gumbo.xs routes GUMBO_NODE_TEMPLATE through the text-node branch, causing strlen() to read beyond the heap object. Parsing attacker-controlled HTML in the default string format or tree format returns the over-read bytes; callback format aborts on the node type and is unaffected.
The record
- CVE
- CVE-2025-15646
- Published
- Jul 1, 2026
- Updated
- Jul 1, 2026
- Vendor
- Best Practical Solutions LLC
- Product
- HTML::Gumbo
- Classifications
- CWE-125, CWE-843
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Jul 1, 2026CVE publishedPublication date reported by the CVE source.
- Jul 1, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <0.19
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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