USN-8588-1: Gawk vulnerabilities
It was discovered that Gawk incorrectly handled memory when processing input using the getline redirection. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-40467) It was discovered that Gawk incorrectly handled certain integer calculations when allocating memory. An attacker could possibly use this issue to cause a denial of service or overwrite heap memory with attacker-controlled data. (CVE-2026-40468) It was discovered that Gawk incorrectly handled certain integer calculations when performing substitutions. An attacker could possibly use this issue to cause a denial of service. (CVE-2026-40469) It was discovered that Gawk incorrectly handled memory when reading directory entries. An attacker could possibly use this issue to cause a denial of service or execute arbitrary code. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-40553)
CSIRTS triage
- What
- Gawk has vulnerabilities that could lead to denial of service or remote code execution due to improper memory handling and integer calculations.
- Who is affected
- Users of Gawk, particularly those on Ubuntu 26.04 LTS.
- Urgency
- Remediation is urgent as these vulnerabilities can be exploited to cause denial of service or execute arbitrary code.
- Action
- Update Gawk to the latest version.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://ubuntu.com/security/notices/USN-8588-1
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-404670.21% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 12% of all scored CVEs.
- Low exploitation riskCVE-2026-404680.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all scored CVEs.
- Low exploitation riskCVE-2026-404690.21% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 12% of all scored CVEs.
- Low exploitation riskCVE-2026-405530.29% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 21% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-40467 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-40468 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-40469 | coverage & exploitation status | NVD · CVE.org |
| CVE-2026-40553 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownCVE-2026-40553: Stack-based buffer overflow in gawkmsrc
- unknownCVE-2026-40467: Use after free in gawkmsrc
- unknownCVE-2026-40468: Heap buffer overflow in gawkmsrc
- unknownCVE-2026-40469: Heap buffer overflow in gawkmsrc
- highCVE-2026-40553: Buffer overflow vulnerability has been found in "extension/readdir.c" program file of gawk (ft…nvd
- criticalCVE-2026-40469: Integer overflow vulnerability has been found in "builtin.c" program file of gawk (do_sub() ro…nvd
- criticalCVE-2026-40468: Integer overflow vulnerability has been found in "builtin.c" program file of gawk. This issue …nvd
- highCVE-2026-40467: Use After Free vulnerability has been found in "io.c" program file of gawk (do_getline_redir()…nvd
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