CVE-2025-39688: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.6% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: nfsd: allow SC_STATUS_FREEABLE when searching via nfs4_lookup_stateid() The pynfs DELEG8 test fails when run against nfsd. It acquires a delegation and then lets the lease time out. It then tries to use the deleg stateid and expects to see NFS4ERR_DELEG_REVOKED, but it gets bad NFS4ERR_BAD_STATEID instead. When a delegation is revoked, it's initially marked with SC_STATUS_REVOKED, or SC_STATUS_ADMIN_REVOKED and later, it's marked with the SC_STATUS_FREEABLE flag, which denotes that it is waiting for s FREE_STATEID call. nfs4_lookup_stateid() accepts a statusmask that includes the status flags that a found stateid is allowed to have. Currently, that mask never includes SC_STATUS_FREEABLE, which means that revoked delegations are (almost) never found. Add SC_STATUS_FREEABLE to the always-allowed status flags, and remove it from nfsd4_delegreturn() since it's now always implied.

Affected products

• Linux Linux Kernel: from 6.11.6, before 6.12 (fixed in 6.12); from 6.12.1, before 6.12.23 (fixed in 6.12.23); from 6.13, before 6.13.11 (fixed in 6.13.11); from 6.14, before 6.14.2 (fixed in 6.14.2); version 6.12 only

Published 2025-04-18. Last modified 2026-07-30.