smb: client: reject userspace cifs.spnego descriptions

Summary

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.spnego descriptions cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as kernel-originating inputs. However, userspace can also create keys of this type through request_key(2) or add_key(2), allowing those fields to be supplied without CIFS origin. Only accept cifs.spnego descriptions while CIFS is using its private spnego_cred to request the key.

Timeline

1. Jun 1, 2026, 12:00 AM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: total

2. Jun 1, 2026, 4:22 PM UTCCVE published
3. Oct 15, 2026, 1:21 AM UTCRecord last updated

Affected versions

• Linux Linux

  From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in 7713bd320ed4fc3d08a227cd8e41242219a16981; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in 9544559e59438a4b609b2fdfa0763d8360572824; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in cf20038657d6d4974349556a34e08fe0490bebbc; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in 2035acfb17221729b1b8ac335e941868a04ca079; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in a3bbda6502a9398b816fa2e71c9a3f955f58013d; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in 91f89c1d83e80417629791fcef6af8140d7d01c8; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in 0aece6685fc80a8de492688ca2315fb86ec379c7; From f1d662a7d5e5322e583aad6b3cfec03d8f27b435 · fixed in 3da1fdf4efbc490041eb4f836bf596201203f8f2

• Linux Linux

  2.6.24

• KernelLinux

  From 2.6.24 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.142; From 6.7.0 · fixed in 6.12.92; From 6.13.0 · fixed in 6.18.34; From 6.19.0 · fixed in 7.0.11

References 8