CVE-2026-45983

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: never defer requests during idmap lookup During v4 request compound arg decoding, some ops (e.g. SETATTR) can trigger idmap lookup upcalls. When those upcall responses get delayed beyond the allowed time limit, cache_check() will mark the request for deferral and cause it to be dropped. This prevents nfs4svc_encode_compoundres from being executed, and thus the session slot flag NFSD4_SLOT_INUSE never gets cleared. Subsequent client requests will fail with NFSERR_JUKEBOX, given that the slot will be marked as in-use, making the SEQUENCE op fail. Fix this by making sure that the RQ_USEDEFERRAL flag is always clear during nfs4svc_decode_compoundargs(), since no v4 request should ever be deferred.

References

Other References

https://git.kernel.org/stable/c/063a6f22478ef929625000a2caf54667725c1dfd https://git.kernel.org/stable/c/243f71ed873ff3feeb6f9b5cb145d63f7188b4c4 https://git.kernel.org/stable/c/3a72c7dedc99b321e0f267e4e999e5baf07c4593 https://git.kernel.org/stable/c/8dff54fe88c0dcd4c55bff9fc2fa6ca968290826 https://git.kernel.org/stable/c/99e17b20fddac19a228d213e00f6b9e1c10daff9 https://git.kernel.org/stable/c/b9abb760db20504240a7147f27934d900cd80b23 https://git.kernel.org/stable/c/d75ec4504a4340b033b15cad0303988b3089dd93 https://git.kernel.org/stable/c/f9c206cdc4266caad6a9a7f46341420a10f03ccb

Frequently Asked Questions

What is CVE-2026-45983? +

In the Linux kernel, the following vulnerability has been resolved: nfsd: never defer requests during idmap lookup During v4 request compound arg decoding, some ops (e.g. SETATTR) can trigger idmap lookup upcalls. When those upcall responses get delayed beyond the allowed time limit, cache_check() will mark the request for deferral and cause it to be dropped. This prevents nfs4svc_encode_compoundres from being executed, and thus the session slot flag NFSD4_SLOT_INUSE never gets cleared. Subsequent client requests will fail with NFSERR_JUKEBOX, given that the slot will be marked as in-use, making the SEQUENCE op fail. Fix this by making sure that the RQ_USEDEFERRAL flag is always clear during nfs4svc_decode_compoundargs(), since no v4 request should ever be deferred.

How do I check if I'm vulnerable to CVE-2026-45983? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Description

References

Other References

Frequently Asked Questions

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