CVE-2026-66485: GNU Cpio

Medium severity, CVSS 4.6. EPSS: 0.2% chance of exploitation in the next 30 days.

GNU cpio is vulnerable to an uncontrolled memory allocation in the make_path function at src/makepath.c. The function uses alloca to allocate stack memory based on the length of argpath, which is derived from an archive-controlled pathname during extraction. A malicious cpio archive containing a sufficiently long nested pathname causes an unbounded stack allocation, resulting in a stack overflow and crash of the cpio process. An attacker who can supply a crafted cpio archive to a victim who extracts it can cause a denial of service. This issue has been fixed in commit 3cd514031371d8aeeaf2048aa10103e02831aaa9

Affected products

• GNU Cpio: up to and including 2.15

Published 2026-08-10. Last modified 2026-08-28.