nfsd: check client ownership when cancelling a copy-notify stateid

Summary

In the Linux kernel, the following vulnerability has been resolved: nfsd: check client ownership when cancelling a copy-notify stateid On the OFFLOAD_CANCEL path (clp != NULL), manage_cpntf_state() freed the target cpntf state without checking ownership. The lookup key st->si_opaque.so_id is allocated cyclically (guessable) and the embedded clientid is the fixed per-net nn->s2s_cp_cl_id, so any authenticated NFSv4.2 client could cancel and free another client's copy-notify stateid. Compare the creating clientid recorded in state->cp_p_clid against the requesting client's cl_clientid and return nfserr_bad_stateid on a mismatch instead of freeing the entry.

Timeline

1. Sep 11, 2026, 7:46 PM UTCCVE published
2. Oct 19, 2026, 8:51 AM UTCRecord last updated

Affected versions

• Linux Linux

  From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in 88daaed26e17e1c7e851859b5bbb4f0e1ab6d0e9; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in 81b2cfe767943922eca906a2a5af23a0ce5d0f35; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in 6bba72b8ee68ad631b94bd439592cba46de54d7d; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in 75268f6cfe26b09a7e4d3216367e87fe9e2a26aa; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in b1eca07303594ca27f5dc360a6946bd7e1f5b04c; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in b42dc26a14b4ad5d6daaada11ec4c70744141c25; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in d801906165cb5cc250d5cbe44935594e170be3e2; From ce0887ac96d35c7105090e166bb0807dc0a0e838 · fixed in 6bdbfab96e0cf25e5f57dac5c09dc1749751a4bf

• Linux Linux

  5.6

• KernelLinux

  From 5.6.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8