CVE-2026-42494: buffer overruns in libfsimage iso9660 handling

Vulnerability summary

CVE-2026-42494 is a medium (CVSS 6.1) Out-of-bounds Read vulnerability in xen. EPSS estimates a 0.11% chance of exploitation in the next 30 days, higher than 1.2% of scored vulnerabilities.

Timeline

1. 28-07-2026
   PublishedVulnerability first disclosed.
2. 28-07-2026
   Last modifiedVulnerability information updated.

Description

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] The directory and Rock Ridge / SUSP walk in libfsimage's iso9660 driver derives several lengths directly from attacker-controlled on-disk fields without validating them: * The directory loop itself assumes a good record length. This is CVE-2026-42494. * The calculation of the System Use area may underflow. This is CVE-2026-42495. * The Rock Ridge extension loop assumes a good (inner) record length. This is CVE-2026-62423. * The Rock Ridge NM record processing assumes a good entry length. This is CVE-2026-62424. * The Rock Ridge CE record processing assumes a good size and offset. This is CVE-2026-62425.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.