Out-of-bounds Read in Xen
CVE-2026-42494
[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.
Vulnerability class: Buffer Overflow
EPSS: 0.001 (1.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H.
Affected products
- Xen — versions consult Xen advisory XSA-497
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-42494?
- CVE-2026-42494 is a medium-severity vulnerability in Xen, classified under Out-of-bounds Read. CVSS score: 6.1/10. Published 2026-07-28.
- How severe is CVE-2026-42494?
- Medium severity. CVSS v3 base score is 6.1 out of 10.