Process crash via wrapped substitution buffer size
Published Jul 13, 2026 · Updated Jul 13, 2026
Integer overflow in GNU Awk 5.4.0 and earlier allows local users to crash 32-bit gawk builds through crafted substitution input. The do_sub routine calculates the result-buffer size with overflowing native-width arithmetic, underallocating storage before replacement data corrupts heap metadata and objects. The flaw requires a 32-bit build and local execution of an attacker-controlled substitution workload, and the grounded impact is a gawk process crash.
Summary
What happened
Integer overflow in GNU Awk 5.4.0 and earlier allows local users to crash 32-bit gawk builds through crafted substitution input. The do_sub routine calculates the result-buffer size with overflowing native-width arithmetic, underallocating storage before replacement data corrupts heap metadata and objects. The flaw requires a 32-bit build and local execution of an attacker-controlled substitution workload, and the grounded impact is a gawk process crash.
The record
- CVE
- CVE-2026-40469
- Published
- Jul 13, 2026
- Updated
- Jul 13, 2026
- Vendor
- The GnuPG Project
- Product
- GNU Awk
- Classifications
- CWE-190
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 13, 2026CVE publishedPublication date reported by the CVE source.
- Jul 13, 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 <=5.4.0
What conditions does exploitation require?
What is affected?
Attacks
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Public exploit references
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