CVE-2025-68349
Description
A flaw null pointer dereference in the Linux kernel NFS functionality was found in the way client does some specific action for existing NFS connection. A client user could use this flaw to crash the server system.
Statement
This bug is caused by a stale state flag (NFS_INO_LAYOUTCOMMIT) remaining set after the pNFS layout has been invalidated, leading to a NULL pointer dereference during layout commit handling. The issue results in a kernel crash when specific NFS writeback paths are executed. As it involves no memory corruption or attacker-controlled data, it represents a denial-of-service condition only. The issue is triggered by a connected NFS client through normal pNFS writeback flows and affects the NFS server kernel, requiring an established NFSv4 session rather than unauthenticated network access.
Mitigation
If NFS service not being used, then disable it to prevent possibility of triggering this bug (and usually it is disabled by default):
sudo systemctl stop nfs-server
sudo systemctl disable nfs-server
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/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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