Heap corruption via wrapped allocation size
Published Jul 13, 2026 · Updated Jul 13, 2026
Integer overflow in builtin.c in GNU Awk 5.4.0 and earlier allows local users to exhaust memory or overwrite heap data via untrusted input. Allocation-size arithmetic in builtin.c can wrap before memory is allocated, so later writes can exceed the undersized heap region. Reachability requires executing a malicious awk script or processing crafted input locally; effects are memory exhaustion, heap corruption, and instability.
Summary
What happened
Integer overflow in builtin.c in GNU Awk 5.4.0 and earlier allows local users to exhaust memory or overwrite heap data via untrusted input. Allocation-size arithmetic in builtin.c can wrap before memory is allocated, so later writes can exceed the undersized heap region. Reachability requires executing a malicious awk script or processing crafted input locally; effects are memory exhaustion, heap corruption, and instability.
The record
- CVE
- CVE-2026-40468
- 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
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What is affected?
Published CVSS scores
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Attacks
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