CVE-2026-74426
Description
A flaw was found in the Linux kernel's AFS (Andrew File System) component. A local user can exploit this by triggering a specific memory allocation condition during a mount operation, leading to a null pointer dereference. This can cause the system to crash, resulting in a Denial of Service (DoS).
Statement
A low impact NULL pointer dereference flaw was found in the Linux kernel's AFS (Andrew File System) filesystem implementation. When an AFS filesystem is mounted with a dynamic root, afs_alloc_sbi() allocates the superblock information with kzalloc and leaves the cell and volume pointers NULL when ctx->dyn_root is set; trace_afs_get_tree() then dereferences those NULL pointers during the mount operation. A local user able to trigger an AFS mount operation can use this flaw to crash the kernel, resulting in a denial of service. This flaw affects the kernel and kernel-rt components in Red Hat Enterprise Linux 9 and 10 as well as the kernel components in Red Hat In-Vehicle OS 2, where the fix has been deferred to a future update because the issue is a low severity local denial of service with low actionability; the residual risk is limited to a local user causing a system crash. Red Hat Enterprise Linux 6, 7, and 8 are not affected because the vulnerable code is not present in those kernels. Red Hat rates the impact of this flaw as Low even though the CVSS:3.1 base score is 5.5 (Moderate), because exploitation requires local access, the flaw can only be used to cause a denial of service, and it has been assessed as having low actionability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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