CVE-2026-5121: libarchive Integer Overflow or Wraparound

Vulnerability summary

CVE-2026-5121 is a high (CVSS 7.5) Integer Overflow or Wraparound vulnerability in libarchive. EPSS estimates a 1.43% chance of exploitation in the next 30 days, higher than 72.5% of scored vulnerabilities.

Timeline

1. 30-03-2026
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

A flaw was found in libarchive. On 32-bit systems, an integer overflow vulnerability exists in the zisofs block pointer allocation logic. A remote attacker can exploit this by providing a specially crafted ISO9660 image, which can lead to a heap buffer overflow. This could potentially allow for arbitrary code execution on the affected system.

• CWE-190Integer Overflow or WraparoundThe product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.