VulnerabilityPublished 13 Jul 2026

CVE-2026-40469: gawk · Integer Overflow Vulnerability Has Been Found

Affects gawkSource GCVE Database

Authoritative record:CVE-2026-40469· Medium 5.1

Not known to be exploited · CVSS 5.1 Medium.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score

5.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

Attack Vector: Local
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: Low
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the Vulnerable System are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 13 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Ubuntu 26.04 LTSgawk`pkg:deb/ubuntu/gawk@1:5.3.2-1ubuntu1?arch=source&distro=resolute`Other threats	Affected =1:5.3.2-1build1 =1:5.3.2-1ubuntu1	Fixed in–
Ubuntu 24.04 LTSgawk`pkg:deb/ubuntu/gawk@1:5.2.1-2build3?arch=source&distro=noble`Other threats	Affected =1:5.2.1-2 =1:5.2.1-2build2 =1:5.2.1-2build3	Fixed in–
Ubuntu 22.04 LTSgawk`pkg:deb/ubuntu/gawk@1:5.1.0-1ubuntu0.1?arch=source&distro=jammy`Other threats	Affected 1:5.1.0-1build1 – 1:5.1.0-1ubuntu0.1 4 affected builds	Fixed in–
Ubuntu 20.04 LTSgawk`pkg:deb/ubuntu/gawk@1:5.0.1+dfsg-1ubuntu0.1?arch=source&distro=focal`Other threats	Affected =1:4.2.1+dfsg-1.1build1 =1:5.0.1+dfsg-1 =1:5.0.1+dfsg-1ubuntu0.1	Fixed in–
Ubuntu Pro 18.04 LTSgawk`pkg:deb/ubuntu/gawk@1:4.1.4+dfsg-1ubuntu0.1~esm1?arch=source&distro=esm-infra/bionic`Other threats	Affected =1:4.1.4+dfsg-1 =1:4.1.4+dfsg-1build1 =1:4.1.4+dfsg-1ubuntu0.1~esm1	Fixed in–
Ubuntu Pro 16.04 LTSgawk`pkg:deb/ubuntu/gawk@1:4.1.3+dfsg-0.1ubuntu0.1~esm1?arch=source&distro=esm-infra/xenial`Other threats	Affected =1:4.1.1+dfsg-1 =1:4.1.3+dfsg-0.1 =1:4.1.3+dfsg-0.1ubuntu0.1~esm1	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Until an official fix is available, users should consider avoiding use of vulnerable 32-bit gawk builds or apply any vendor-provided workarounds once published.

Description

An integer overflow vulnerability exists in the do_sub() routine of the builtin.c file in gawk, affecting 32-bit builds of gawk version 5.4.0 and below. This flaw can lead to heap metadata and object overwrites, causing the program to crash. The issue impacts multiple specific gawk package builds primarily found in Ubuntu distributions. No known exploits are reported in the wild, and the severity is assessed as medium.

Impact

Successful exploitation of this integer overflow can cause heap metadata and object corruption, leading to crashes of the gawk program on affected 32-bit systems. This may result in denial of service but does not explicitly indicate code execution or data leakage.

Summary

CVE-2026-40469 describes an integer overflow vulnerability in the do_sub() routine within the builtin.c source file of gawk. The vulnerability affects 32-bit builds of gawk versions 5.4.0 and earlier. Exploitation could overwrite heap metadata and objects, resulting in program crashes. The vulnerability is confirmed in various Ubuntu package builds of gawk. There is no indication of active exploitation or a publicly available patch at this time.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 02:49 UTC

Technical details

References

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