CVE-2025-71080
Description
A race condition vulnerability was found in the Linux kernel's IPv6 routing subsystem on PREEMPT_RT kernels. When rt6_get_pcpu_route() returns NULL and the task is preempted, another task can install a per-CPU route entry. When the original task resumes and attempts cmpxchg() in rt6_make_pcpu_route(), the operation fails because the pointer is no longer NULL, triggering a BUG_ON crash.
Statement
This vulnerability specifically affects PREEMPT_RT (real-time) kernel configurations during IPv6 routing operations. Standard kernel builds are not affected as the race window does not exist without RT preemption. The crash requires specific timing conditions and concurrent IPv6 route operations on the same CPU.
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 | 5.5 | 7.5 |
| Attack Vector | Local | Local | Network |
| Attack Complexity | Low | Low | Low |
| Privileges Required | Low | Low | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/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
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)
Integrity,Confidentiality
Technical Impact: Modify Application Data; Read Application Data
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