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Linux Kernel CVE-2026-72373

| EUVDEUVD-2026-59272 HIGH
2026-08-15 Linux GHSA-4h6c-mrxr-5r6x
Denial Of Service Linux Red Hat Suse
7.5
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
vuln.today AI
5.9 MEDIUM

AC:H reflects the non-default AFS deployment prerequisite; all other metrics align with unauthenticated remote DoS with no confidentiality or integrity impact.

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
SUSE
5.5 MEDIUM
AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Red Hat
5.5 MEDIUM
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

Lifecycle Timeline

5
Analysis Generated
Aug 17, 2026 - 08:52 vuln.today
CVSS changed
Aug 17, 2026 - 06:22 NVD
7.5 (HIGH)
Patch available
Aug 15, 2026 - 07:20 EUVD
CVE Published
Aug 15, 2026 - 05:56 cve.org
HIGH 7.5
CVE Published
Aug 15, 2026 - 05:56 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix missing NULL pointer check in afs_break_some_callbacks()

Fix afs_break_some_callbacks() to check to see if afs_lookup_volume_rcu() returned NULL (e.g. the specified volume is unknown).

AnalysisAI

Denial-of-service in the Linux kernel's AFS (Andrew File System) client allows a remote attacker to crash the kernel by triggering a NULL pointer dereference in afs_break_some_callbacks(). The flaw exists because afs_lookup_volume_rcu() can return NULL when a referenced volume is unknown, and this return value is used without a NULL check. No public exploit code exists and EPSS sits at 0.21%, though the official CVSS scores it 7.5 (High) due to a network attack vector with no authentication required.

Technical ContextAI

The AFS subsystem in the Linux kernel implements the Andrew File System, a distributed network filesystem. The function afs_break_some_callbacks() handles server-initiated callback breaks - notifications from an AFS file server to its clients that cached data is stale. This function calls afs_lookup_volume_rcu() to find the local volume record corresponding to the server's notification. When the server references a volume ID that is not known locally (e.g., due to a race, misconfiguration, or a malicious/forged AFS server message), afs_lookup_volume_rcu() returns NULL. Without a NULL guard before dereferencing that pointer, the kernel encounters a NULL pointer dereference (consistent with CWE-476, though NVD lists CWE as N/A). The AFS client code is reached via the RxRPC transport protocol over UDP. CPE data confirms the affected codebase as cpe:2.3:a:linux:linux and the vulnerability is introduced from commit 8230fd8217b7ea76f838ae88e4a5a8e54f37099f onward.

RemediationAI

The primary fix is to upgrade the Linux kernel to a patched stable release: 6.12.97 or later in the 6.12 branch, 6.18.40 or later in the 6.18 branch, 7.1.5 or later in the 7.1 branch, or 7.2-rc2 or later in the mainline branch. The upstream fix commits are documented at https://git.kernel.org/stable/c/a99a617701186dc68c7b330d35fc2253f48e2ab2 and companion stable commits. Distribution-packaged kernels (RHEL, Ubuntu, SUSE, Debian) should be updated as vendors backport the fix. As a compensating control for systems where an immediate kernel update is not feasible, disabling or unmounting AFS client functionality eliminates the attack surface entirely - this can be done by unloading the kafs kernel module (modprobe -r kafs) if AFS is not operationally required; this has no side effects beyond loss of AFS filesystem access. Systems not using AFS are not exposed.

Same technique Denial Of Service

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Vendor StatusVendor

SUSE

Severity: Moderate
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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CVE-2026-72373 vulnerability details – vuln.today
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