CVE-2026-68438
Description
A flaw was found in the Linux kernel. When CSD (Call Single Data) lock debugging is enabled, the csd_lock() function's acquisition of the CSD lock is not atomic. This allows multiple central processing units (CPUs) to concurrently access and modify the same CSD data. A local attacker could exploit this race condition, causing the target CPU to become stuck in a loop while processing the call_single_queue. This can lead to soft-lockup warnings or system panics, effectively resulting in a Denial of Service (DoS).
Statement
This issue affects SMP cross-call debugging when CONFIG_SMP_CSD_LOCK_WAIT_DEBUG is enabled. Multiple CPUs can concurrently prepare the same destination csd_data, breaking the single-writer assumption in csd_lock(). Default production kernels without this debug option are not affected.
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)
Integrity,Confidentiality,Other
Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
