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GNU gawk CVE-2026-40467

MEDIUM
Use After Free (CWE-416)
2026-07-13 CERT-PL
5.1
CVSS 4.0 · Vendor: CERT-PL
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Severity by source

Vendor (CERT-PL) PRIMARY
5.1 MEDIUM
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today AI
4.0 MEDIUM

Local vector requires script execution access; crash-only outcome yields A:L with no confidentiality or integrity impact and unchanged scope.

3.1 AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
4.0 AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Primary rating from Vendor (CERT-PL).

CVSS VectorVendor: CERT-PL

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
X

Lifecycle Timeline

2
Analysis Generated
Jul 13, 2026 - 13:16 vuln.today
CVE Published
Jul 13, 2026 - 12:07 cve.org
MEDIUM 5.1

DescriptionCVE.org

Use After Free vulnerability has been found in "io.c" program file of gawk (do_getline_redir() routine). This issue may lead to a crash. It affects gawk in versions 5.4.0 and below.

AnalysisAI

Use-after-free memory corruption in gawk's do_getline_redir() routine within io.c allows a local attacker to crash the gawk process, causing a denial of service. All gawk versions 5.4.0 and below are affected, as confirmed by CERT-PL and an upstream patch commit. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Access
Gain local access or script injection point
Delivery
Craft AWK script with getline I/O redirection
Exploit
Submit script to vulnerable gawk (≤5.4.0)
Execution
Trigger use-after-free in do_getline_redir()
Impact
gawk process crashes (DoS)

Vulnerability AssessmentAI

Exploitation Exploitation requires the ability to execute or influence an AWK script processed by a vulnerable version of gawk (5.4.0 or below) on the local system, specifically one that exercises the getline I/O redirection functionality handled by the do_getline_redir() routine in io.c. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 4.0 score of 5.1 (Medium) with vector AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N accurately characterizes this as a low-impact, locally-triggered denial-of-service issue. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario An attacker with local shell access, or the ability to supply a crafted AWK script to an automated pipeline running gawk, provides input that exercises the getline I/O redirection code path in do_getline_redir(). The use-after-free is triggered, causing gawk to crash and disrupting any dependent process or pipeline. …
Remediation Apply the upstream patch available via commit a2d18c74109e41bec29a23098eba2e00057286d8 in the GNU gawk repository (https://cgit.git.savannah.gnu.org/cgit/gawk.git/commit/?id=a2d18c74109e41bec29a23098eba2e00057286d8). … Detailed patch versions, workarounds, and compensating controls in full report.

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CVE-2026-40467 vulnerability details – vuln.today

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