Linux Kernel up to 6.12.108/6.18.49/7.2.3 nfsd nfsd_file_net_dispose null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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6.2$0-$5k0.22+

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.108/6.18.49/7.2.3. It has been declared as critical. This affects the function nfsd_file_net_dispose of the component nfsd. The manipulation results in null pointer dereference. This vulnerability is reported as CVE-2026-93212. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.12.108/6.18.49/7.2.3. Affected is the function nfsd_file_net_dispose of the component nfsd. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: nfsd: guard nfsd_serv deref in nfsd_file_net_dispose nfsd_file_net_dispose() is the consumer side of l->freeme: the nfsd service thread loop calls it to drain entries that the filecache garbage collector and shrinker append via nfsd_file_dispose_list_delayed(). During per-net teardown, nn->nfsd_serv is cleared before the filecache laundrette is shut down, so the service thread can still run a dispose pass that finds more than eight entries on l->freeme and dereferences a NULL svc_serv: nfsd service thread loop nfsd_file_net_dispose(nn) if (!list_empty(&l->freeme)) { ... svc_wake_up(nn->nfsd_serv); /* nn->nfsd_serv == NULL */ } The sibling helper nfsd_file_dispose_list_delayed() already documents this ordering and caches nn->nfsd_serv into a local before testing it for NULL. nfsd_file_net_dispose() was introduced with the same raw svc_wake_up(nn->nfsd_serv) call and never picked up the guard. Fix by loading nn->nfsd_serv into a local svc_serv pointer and only calling svc_wake_up() when it is non-NULL, matching the pattern in nfsd_file_dispose_list_delayed().

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-93212 since 09/17/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/24/2026).

Upgrading to version 6.12.109, 6.18.50, 7.2.4 or 7.3-rc1 eliminates this vulnerability. Applying the patch f4776c1c4b38fbc459420321c8ece87d0f7f95fb/59baf45a06435194005fc5fa9a42d89f77a30432/766170b4fd2daaf5c4d6735560101474e18edab6/9f1ddfc8cb9076592401a611eb3a44d36186d014 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

Vendor

Name

Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.109/6.18.50/7.2.4/7.3-rc1
Patch: f4776c1c4b38fbc459420321c8ece87d0f7f95fb/59baf45a06435194005fc5fa9a42d89f77a30432/766170b4fd2daaf5c4d6735560101474e18edab6/9f1ddfc8cb9076592401a611eb3a44d36186d014

Timelineinfo

09/17/2026 CVE reserved
09/24/2026 +7 days Advisory disclosed
09/24/2026 +0 days VulDB entry created
09/24/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-93212 (🔒)
GCVE (CVE): GCVE-0-2026-93212
GCVE (VulDB): GCVE-100-409422

Entryinfo

Created: 09/24/2026 17:49
Changes: 09/24/2026 17:49 (59)
Complete: 🔍
Cache ID: 216::103

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