CVE-2025-21666: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: vsock: prevent null-ptr-deref in vsock_*[has_data|has_space] Recent reports have shown how we sometimes call vsock_*_has_data() when a vsock socket has been de-assigned from a transport (see attached links), but we shouldn't. Previous commits should have solved the real problems, but we may have more in the future, so to avoid null-ptr-deref, we can return 0 (no space, no data available) but with a warning. This way the code should continue to run in a nearly consistent state and have a warning that allows us to debug future problems.

Affected products

• Linux Linux Kernel: from 5.5, before 5.15.177 (fixed in 5.15.177); from 5.16, before 6.1.127 (fixed in 6.1.127); from 6.2, before 6.6.74 (fixed in 6.6.74); from 6.7, before 6.12.11 (fixed in 6.12.11); version 6.13 only

Published 2025-01-31. Last modified 2026-06-17.