Medium 5.5Published May 27, 2026

CVE-2026-45983nfsd: never defer requests during idmap lookup

Updated under an hour ago (Oct 27, 2026, 1:23 AM ET)

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Exploited in the last 30 days

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.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: May 27, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before b9abb760db20504240a7147f27934d900cd80b23; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before 3a72c7dedc99b321e0f267e4e999e5baf07c4593; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before 99e17b20fddac19a228d213e00f6b9e1c10daff9; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before 243f71ed873ff3feeb6f9b5cb145d63f7188b4c4; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before 063a6f22478ef929625000a2caf54667725c1dfd; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before d75ec4504a4340b033b15cad0303988b3089dd93; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before 8dff54fe88c0dcd4c55bff9fc2fa6ca968290826; from 2f425878b6a71571341dcd3f9e9d1a6f6355da9c before f9c206cdc4266caad6a9a7f46341420a10f03ccb	CNA record
linux linux_kernel linux:linux_kernel	from 2.6.30 before 5.10.252; from 5.11 before 5.15.202; from 5.16 before 6.1.165; from 6.2 before 6.6.128; from 6.7 before 6.12.75; from 6.13 before 6.18.14; from 6.19 before 6.19.4	NVD

References

References

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

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.