Quick answers
- Is CVE-2026-42495 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-42495 being exploited in the wild.
- How severe is CVE-2026-42495?
- Informational severity, with a CVSS score of 8.8, published 28 July 2026.
- Which products and versions are affected?
- Xen Project Xen 3.2 and later.
- Is there a fix for CVE-2026-42495?
- A patch was published on 2026-07-28. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-42495 attacked?
- It is attacked with local access, in an operating system.
- Am I affected by CVE-2026-42495?
- Check whether you run Xen Project Xen at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A vulnerability exists in the libfsimage iso9660 driver's handling of directory and Rock Ridge / SUSP walks. Specifically, CVE-2026-42495 involves an integer underflow during the calculation of the System Use area size because the driver derives lengths directly from attacker-controlled on-disk fields without validation. An attacker with the ability to provide a malicious ISO image to the pygrub bootloader can trigger a buffer overrun. This allows a guest VM to escalate privileges to the domain construction tools (typically Dom0), leading to a full host compromise. A patch is available from the Xen Project (XSA-497).
Affected products
- Xen Project Xen 3.2 and later
Timeline
- 2026-07-28: disclosed
- 2026-07-28: advisory
- 2026-07-28: patched