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CVE-2026-45983

Updated on 27 May 2026

Severity

5.5 Medium severity

Details

CVSS score
5.5
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Links
NISTCIRCLRHELUbuntu

Overview

About vulnerability

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.

Details

Affected product:
AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 6 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
Affected packages:
linux-hwe @ 4.15.0 (+18 more)

Fixes

KernelCare state

Live-patch status from KernelCare for each operating system.

Operating system Status Covered kernels
Amazon Linux 2023 Planned —
Debian 11 Released
37 kernels
  • 5.10.46-5
  • 5.10.70-1
  • 5.10.46-4
  • 5.10.84-1
  • 5.10.92-1
  • 5.10.92-2
  • 5.10.103-1
  • 5.10.106-1
  • 5.10.113-1
  • 5.10.120-1
  • 5.10.127-1
  • 5.10.127-2
  • 5.10.136-1
  • 5.10.140-1
  • 5.10.149-1
  • 5.10.149-2
  • 5.10.158-2
  • 5.10.162-1
  • 5.10.179-1
  • 5.10.179-2
  • 5.10.179-3
  • 5.10.179-5
  • 5.10.191-1
  • 5.10.197-1
  • 5.10.178-3
  • 5.10.205-2
  • 5.10.205-1
  • 5.10.209-2
  • 5.10.216-1
  • 5.10.218-1
  • 5.10.221-1
  • 5.10.223-1
  • 5.10.226-1
  • 5.10.234-1
  • 5.10.237-1
  • 5.10.244-1
  • 5.10.247-1
Debian 11 cloud Released
17 kernels
  • 5.10.113-1
  • 5.10.179-2
  • 5.10.179-3
  • 5.10.179-5
  • 5.10.191-1
  • 5.10.197-1
  • 5.10.205-2
  • 5.10.209-2
  • 5.10.216-1
  • 5.10.218-1
  • 5.10.221-1
  • 5.10.223-1
  • 5.10.226-1
  • 5.10.234-1
  • 5.10.237-1
  • 5.10.244-1
  • 5.10.247-1
Debian 13 Planned —
Ubuntu 22.04 Planned —
Ubuntu 24.04 Released
45 kernels
  • 6.8.0-35.35
  • 6.8.0-38.38
  • 6.8.0-36.36
  • 6.8.0-39.39
  • 6.8.0-40.40
  • 6.8.0-41.41
  • 6.8.0-44.44
  • 6.8.0-45.45
  • 6.8.0-31.31
  • 6.8.0-47.47
  • 6.8.0-48.48
  • 6.8.0-49.49
  • 6.8.0-50.51
  • 6.8.0-51.52
  • 6.8.0-52.53
  • 6.8.0-54.56
  • 6.8.0-55.57
  • 6.8.0-53.55
  • 6.8.0-56.58
  • 6.8.0-57.59
  • 6.8.0-58.60
  • 6.8.0-59.61
  • 6.8.0-60.63
  • 6.8.0-62.65
  • 6.8.0-63.66
  • 6.8.0-64.67
  • 6.8.0-71.71
  • 6.8.0-78.78
  • 6.8.0-79.79
  • 6.8.0-84.84
  • 6.8.0-85.85
  • 6.8.0-83.83
  • 6.8.0-86.87
  • 6.8.0-87.88
  • 6.8.0-88.89
  • 6.8.0-90.91
  • 6.8.0-94.96
  • 6.8.0-100.100
  • 6.8.0-101.101
  • 6.8.0-106.106
  • 6.8.0-107.107
  • 6.8.0-110.110
  • 6.8.0-111.111
  • 6.8.0-117.117
  • 6.8.0-124.124
Ubuntu 24.04 AWS Planned —