CVE-2026-62430 x86: Out-of-bounds read in vRTC emulation
A race condition in Xen's vRTC emulation allows a guest to trigger an out-of-bounds read, potentially disclosing host memory contents.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-62430?
CVE-2026-62430 is a high-severity vulnerability in Xen, published on 28 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Accesses to the CMOS memory contents are done using an indirect IO port pair. Therefore Xen needs to cache the guest chosen index, and one of the usages of the index didn't take the necessary locking to avoid concurrent changes. As a result, a guest could change the index after it being checked, causing a subsequent out-of-bound read access to the contents of an array.
Weakness: CWE-362
Which versions are affected by CVE-2026-62430?
How do I fix CVE-2026-62430?
Apply the vendor's patch.
Is CVE-2026-62430 being exploited?
There is no known exploitation of CVE-2026-62430 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-62430, DEBIAN-CVE-2026-62430, GHSA-w4qm-qcx6-wmw8, UBUNTU-CVE-2026-62430.