CVE-2025-71080
Medium · 5.5CVSS
5.5
EPSS
0.3%
Published
Jan 13, 2026
CISA due date
—
The record
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT On PREEMPT_RT kernels, after rt6_get_pcpu_route() returns NULL, the current task can be preempted. Another task running on the same CPU may then execute rt6_make_pcpu_route() and successfully install a pcpu_rt entry. When the first task resumes execution, its cmpxchg() in rt6_make_pcpu_route() will fail because rt6i_pcpu is no longer NULL, triggering the BUG_ON(prev). It's easy to reproduce it by adding mdelay() after rt6_get_pcpu_route(). Using preempt_disable/enable is not appropriate here because ip6_rt_pcpu_alloc() may sleep. Fix this by handling the cmpxchg() failure gracefully on PREEMPT_RT: free our allocation and return the existing pcpu_rt installed by another task. The BUG_ON is replaced by WARN_ON_ONCE for non-PREEMPT_RT kernels where such races should not occur.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Linux | Kernel | 6.12.0 | 6.12.64 |
| openSUSE:Leap 16.0 | dtb-aarch64 | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-64kb | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-azure | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-default | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-default-base | 0 | 6.12.0-160000.26.1.160000.2.7 |
| openSUSE:Leap 16.0 | kernel-docs | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-kvmsmall | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-obs-build | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-obs-qa | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-rt | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-source | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-syms | 0 | 6.12.0-160000.26.1 |
| openSUSE:Leap 16.0 | kernel-zfcpdump | 0 | 6.12.0-160000.26.1 |
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