CVE-2026-23107
Description
A flaw was found in the Linux kernel on arm64 architectures. When restoring a ZA signal context, the kernel may fail to allocate the necessary memory (sve_state), leading to a NULL pointer dereference. A local, unprivileged user can exploit this vulnerability, potentially causing the kernel to crash and resulting in a Denial of Service (DoS).
Statement
A local NULL pointer dereference can occur on arm64 when restoring a ZA signal context because restore_za_context can set TIF_SME without ensuring current thread sve_state is allocated. In uncommon but legitimate scenarios such as process save and restore workflows using CRIU the signal context may not have been created by the same kernel task and there is no guarantee that sve_state exists. In that state userspace can enter streaming mode while sve_state is NULL and a later kernel attempt to save register state can dereference NULL in sve_save_state and crash the kernel. For the CVSS the PR is N because an unprivileged local process can reach signal return paths without special rights. The issue is not network reachable. Impact is denial of service via kernel crash.
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 | 6.2 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: 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.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
