CVE-2026-62435 grant-table: version change racing with other operations
A race condition in Xen's grant table version switching allows attackers to cause denial of service or privilege escalation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-62435?
CVE-2026-62435 is a medium-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
[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.]
With the introduction of Grant Table v2 came the requirement to be able to switch between versions. Switching from v1 to v2 reduces the number of valid grant references, as a bigger shared entry structure is then needed while the shared table doesn't change size. Switching from v2 back to v1 the status frames, which are separate in v2, go away.
Code holding, but intermediately dropping and then re-acquiring the grant table lock, sometimes wrongly assumes that said properties wouldn't change across the window in time where the lock is not being held.
The v1 -> v2 issue is CVE-2026-62435.
The v2 -> v1 issue is CVE-2026-62436.
Weakness: CWE-362
Which versions are affected by CVE-2026-62435?
How do I fix CVE-2026-62435?
Apply the vendor's patch.
Is CVE-2026-62435 being exploited?
There is no known exploitation of CVE-2026-62435 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-62435, DEBIAN-CVE-2026-62435, GHSA-38wq-hqmp-4jj6, UBUNTU-CVE-2026-62435.