Linux Kernel up to 6.19.3 nfsd cache_check privilege escalation

CVSS Meta Temp Score
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CTI Interest Score
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6.6$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.19.3 and classified as critical. Affected by this vulnerability is the function cache_check of the component nfsd. Performing a manipulation results in an unknown weakness. This vulnerability is identified as CVE-2026-45983. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.19.3. This affects the function cache_check of the component nfsd. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-45983 since 05/13/2026. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/22/2026).

The vulnerability scanner Nessus provides a plugin with the ID 321690 (SUSE SLES12 Security Update : kernel (SUSE-SU-2026:2450-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.14 or 6.19.4 eliminates this vulnerability. Applying the patch b9abb760db20504240a7147f27934d900cd80b23/3a72c7dedc99b321e0f267e4e999e5baf07c4593/99e17b20fddac19a228d213e00f6b9e1c10daff9/243f71ed873ff3feeb6f9b5cb145d63f7188b4c4/063a6f22478ef929625000a2caf54667725c1dfd/d75ec4504a4340b033b15cad0303988b3089dd93/8dff54fe88c0dcd4c55bff9fc2fa6ca968290826/f9c206cdc4266caad6a9a7f46341420a10f03ccb is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (321690). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.8
VulDB Meta Temp Score: 6.6

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 321690
Nessus Name: SUSE SLES12 Security Update : kernel (SUSE-SU-2026:2450-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.252/5.15.202/6.1.165/6.6.128/6.12.75/6.18.14/6.19.4
Patch: b9abb760db20504240a7147f27934d900cd80b23/3a72c7dedc99b321e0f267e4e999e5baf07c4593/99e17b20fddac19a228d213e00f6b9e1c10daff9/243f71ed873ff3feeb6f9b5cb145d63f7188b4c4/063a6f22478ef929625000a2caf54667725c1dfd/d75ec4504a4340b033b15cad0303988b3089dd93/8dff54fe88c0dcd4c55bff9fc2fa6ca968290826/f9c206cdc4266caad6a9a7f46341420a10f03ccb

Timelineinfo

05/13/2026 CVE reserved
05/27/2026 +14 days Advisory disclosed
05/27/2026 +0 days VulDB entry created
06/22/2026 +26 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-45983 (🔒)
GCVE (CVE): GCVE-0-2026-45983
GCVE (VulDB): GCVE-100-366201

Entryinfo

Created: 05/27/2026 17:13
Updated: 06/22/2026 14:44
Changes: 05/27/2026 17:13 (58), 06/16/2026 10:28 (11), 06/22/2026 14:44 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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