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Linux KernelOperating system · Linux

CVE-2026-45983

MEDIUM · 5.5 CVSS v3.1 Published 2026-05-27
Fix available
A fix is available. Upgrade to 5.10.252 / 5.15.202 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.30, < 5.10.252>= 5.11, < 5.15.202>= 5.16, < 6.1.165>= 6.2, < 6.6.128>= 6.7, < 6.12.75>= 6.13, < 6.18.14>= 6.19, < 6.19.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.252 / 5.15.202 / 6.1.165 or later
Fixed in 5.10.2525.15.2026.1.165
Vendor patch git.kernel.org →
Recommended fix High confidence

5.10.252, 5.15.202, 6.1.165, or 6.6.128 (depending on current branch)

  1. 1. Identify the current running kernel version using 'uname -r'
  2. 2. Check which version range your current kernel falls into from the affected versions: >= 2.6.30, < 5.10.252; >= 5.11, < 5.15.202; >= 5.16, < 6.1.165; >= 6.2, < 6.6.128
  3. 3. Upgrade the Linux kernel to the minimum fixed version for your branch: if using 5.10.x upgrade to >= 5.10.252; if using 5.11-5.15.x upgrade to >= 5.15.202; if using 5.16-6.1.x upgrade to >= 6.1.165; if using 6.2-6.6.x upgrade to >= 6.6.128
  4. 4. Update bootloader configuration if necessary (e.g., update-grub for GRUB)
  5. 5. Reboot the system into the new kernel
  6. 6. Verify the fix is applied by checking the kernel version matches one of the fixed releases
Caveat Kernel upgrades may require updated drivers or system configuration adjustments; test in staging environment before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-45983 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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