Memory corruption via wrapped regexp bytecode offset
Published Oct 16, 2025 · Updated Oct 16, 2025
Integer overflow in QuickJS 2025-04-26 allows context-dependent attackers to corrupt memory through a crafted regular expression. libregexp stores DynBuf's size_t bytecode length in signed int offsets; once the bytecode exceeds 2^31 bytes, re_parse_disjunction adds a negative position to the buffer pointer and put_u32 writes out of bounds. Reachability requires an execution path that compiles an extremely large regular expression, and the resulting write can corrupt the hosting process.
Summary
What happened
Integer overflow in QuickJS 2025-04-26 allows context-dependent attackers to corrupt memory through a crafted regular expression. libregexp stores DynBuf's size_t bytecode length in signed int offsets; once the bytecode exceeds 2^31 bytes, re_parse_disjunction adds a negative position to the buffer pointer and put_u32 writes out of bounds. Reachability requires an execution path that compiles an extremely large regular expression, and the resulting write can corrupt the hosting process.
The record
- CVE
- CVE-2025-62495
- Published
- Oct 16, 2025
- Updated
- Oct 16, 2025
- Vendor
- Fabrice Bellard
- Product
- QuickJS
- Classifications
- CWE-191, CAPEC-175, T1203
- Attack vector
- adjacent
- Privileges
- authenticated
Timeline
How it unfolded
- Oct 16, 2025CVE publishedPublication date reported by the CVE source.
- Oct 16, 2025Record 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=2025-04-26 <2025-09-13
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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