What’s Vulnerable › Vulnerabilities

CVE-2026-89694: nfsd: check client ownership when cancelling a copy-notify stateid

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-11 · updated 2026-10-19

Description

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.

Affected products

• Linux kernel: 5.6 — fixed in 7.3

How to fix

Upgrade to a fixed version: Linux kernel 7.3. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/6bba72b8ee68ad631b94bd439592cba46de54d7d
• https://git.kernel.org/stable/c/6bdbfab96e0cf25e5f57dac5c09dc1749751a4bf
• https://git.kernel.org/stable/c/75268f6cfe26b09a7e4d3216367e87fe9e2a26aa
• https://git.kernel.org/stable/c/81b2cfe767943922eca906a2a5af23a0ce5d0f35
• https://git.kernel.org/stable/c/88daaed26e17e1c7e851859b5bbb4f0e1ab6d0e9
• https://git.kernel.org/stable/c/b1eca07303594ca27f5dc360a6946bd7e1f5b04c
• https://git.kernel.org/stable/c/b42dc26a14b4ad5d6daaada11ec4c70744141c25
• https://git.kernel.org/stable/c/d801906165cb5cc250d5cbe44935594e170be3e2

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