What’s Vulnerable › Vulnerabilities

CVE-2026-66485: Uncontrolled Memory Allocation in GNU cpio

• Severity: medium (CVSS 4.6 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-10 · updated 2026-10-24
• Weakness: CWE-789

Description

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: through 2.15

References

• https://cert.pl/en/posts/2026/08/CVE-2026-66484
• https://git.savannah.gnu.org/cgit/cpio.git

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