CVE-2026-40469

Heap buffer overflow in gawk

Published Jul 13, 2026 CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed
Description
Integer overflow vulnerability has been found in "builtin.c" program file of gawk (do_sub() routine). This issue could be used to overwrite gawk heap metadata and objects causing the program to crash. It affects 32-bit builds of gawk in versions 5.4.0 and below.

Analysis

AI-generated

Technical impact

An integer overflow occurs in gawk’s do_sub routine, which can corrupt heap metadata and object structures on the heap, causing the program to crash; the flaw is limited to 32‑bit builds of gawk version 5.4.0 and earlier and represents a classic overflow weakness (CWE‑190).

Affected Systems

GNU gawk 5.4.0 and earlier running as 32‑bit binaries are affected; no other vendors or product lines are listed, so systems relying on legacy gawk binaries from this version range are at risk.

Risk and Exploitability

The CVSS score of 5.1 indicates a moderate risk level. The EPSS score of less than 1% suggests a very low probability of exploitation in the wild. The vulnerability is not listed in CISA KEV. Exploitation would require crafted input to a running gawk instance, making the likely attack vector local or on systems where an attacker can execute gawk scripts, with the principal consequence being a denial of service due to a crash; no privilege escalation or data exfiltration is indicated.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Upgrade to gawk 5.4.1 or newer to eliminate the integer overflow bug.
  • If an upgrade is not immediately possible, limit the use of the do_sub feature or run user‑supplied scripts under restricted privileges to reduce the impact of a crash.
  • Configure monitoring or logging to detect abnormal termination of gawk processes and alert administrators.
  • Ensure that input data passed to gawk scripts is validated or sanitized to avoid triggering the overflow; consider imposing size limits on input.

Generated by OpenCVE AI on July 31, 2026 at 11:37 UTC.

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8588-1 Gawk vulnerabilities
History
Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

cvssV3_1

{'score': 2.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L'}

threat_severity

Moderate

Type Values Removed Values Added
First Time appeared Gnu
Gnu gawk
Vendors & Products Gnu
Gnu gawk
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description Integer overflow vulnerability has been found in "builtin.c" program file of gawk (do_sub() routine). This issue could be used to overwrite gawk heap metadata and objects causing the program to crash. It affects 32-bit builds of gawk in versions 5.4.0 and below.
Title Heap buffer overflow in gawk
Weaknesses CWE-190
References
Metrics cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}

Weaknesses
  • CWE-190

    Integer Overflow or Wraparound

Sources

Status
PUBLISHED
Assigner
CERT-PL
Published
Updated
Jul 13, 2026, 1:01 PM
Reserved
Apr 13, 2026, 2:44 PM
Status
Analyzed
Published
Jul 13, 2026, 1:16 PM
Modified
Oct 24, 2026, 10:10 PM
Severity
Moderate
Public date
Jul 13, 2026, 12:07 PM