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.

A flaw was found in the Linux kernel's Network File System version 4 (NFSv4) daemon (nfsd). When processing NFSv4 requests, delayed responses from idmap lookups can cause requests to be dropped. This issue prevents the session slot from being properly cleared, leading to subsequent client requests failing with an NFSERR_JUKEBOX error. A remote attacker could exploit this to cause a Denial of Service (DoS) for affected NFSv4 clients.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Affected kernel Red Hat Enterprise Linux 7 Affected kernel-rt Red Hat Enterprise Linux 8 Affected kernel Red Hat Enterprise Linux 8 Affected kernel-rt Red Hat Enterprise Linux 9 Affected kernel Red Hat Enterprise Linux 9 Affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-45983 https://nvd.nist.gov/vuln/detail/CVE-2026-45983 https://lore.kernel.org/linux-cve-announce/2026052739-CVE-2026-45983-59f2@gregkh/T