Heap disclosure via self-aliased entity decoding
Published Jun 4, 2026 · Updated Jun 4, 2026
Use-after-free in HTML::Entities before 3.84 allows attackers to disclose adjacent heap contents through crafted entity decoding. The _decode_entities XS routine retains a pointer to an entity-hash value that aliases the input scalar, then grow_gap reallocates that scalar and leaves the pointer dangling. Exploitation requires attacker-controlled entity data and a self-referential, self-aliased hash value; the subsequent copy exposes adjacent heap bytes in the destination scalar.
Summary
What happened
Use-after-free in HTML::Entities before 3.84 allows attackers to disclose adjacent heap contents through crafted entity decoding. The _decode_entities XS routine retains a pointer to an entity-hash value that aliases the input scalar, then grow_gap reallocates that scalar and leaves the pointer dangling. Exploitation requires attacker-controlled entity data and a self-referential, self-aliased hash value; the subsequent copy exposes adjacent heap bytes in the destination scalar.
The record
- CVE
- CVE-2026-8829
- Published
- Jun 4, 2026
- Updated
- Jun 4, 2026
- Vendor
- Olaf Alders
- Product
- HTML::Entities
- Classifications
- CWE-416
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 4, 2026CVE publishedPublication date reported by the CVE source.
- Jun 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
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Is a vulnerable build present?
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- Affected versionversion=0 <3.84
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Published CVSS scores
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Attacks
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