Vulnerability · Published Jul 28, 2026 · Assigned by XEN
CVE-2026-62436grant-table: version change racing with other operations
Medium 6.5
In plain English
A medium-severity race condition in Xen from Xen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.21 | xen | 4.19.6-r0 | ALPINE-CVE-2026-62436 |
| Alpine:v3.22 | xen | 4.20.4-r0 | ALPINE-CVE-2026-62436 |
| Alpine:v3.23 | xen | 4.20.4-r0 | ALPINE-CVE-2026-62436 |
| Alpine:v3.24 | xen | 4.21.2-r0 | ALPINE-CVE-2026-62436 |
| Debian:12 | xen | 4.17.7-0+deb12u1 | DEBIAN-CVE-2026-62436 |
| Debian:13 | xen | 4.20.3+127-gc42374a105-0+deb13u1 | DEBIAN-CVE-2026-62436 |
| Debian:14 | xen | 4.20.3+127-gc42374a105-1 | DEBIAN-CVE-2026-62436 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-62436 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-62436 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2026-62436 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2026-62436 |
Affected products (as reported)
Weakness: CWE-362 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L