High 7.5Published Jan 13, 2026

CVE-2025-71080ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT

Updated under an hour ago (Oct 28, 2026, 5:40 AM ET)

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Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Aug 5, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from d2d6422f8bd17c6bb205133e290625a564194496 before 1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66; from d2d6422f8bd17c6bb205133e290625a564194496 before 787515ccb2292f82eb0876993129154629a49651; from d2d6422f8bd17c6bb205133e290625a564194496 before 1adaea51c61b52e24e7ab38f7d3eba023b2d050d	CNA record
linux linux_kernel linux:linux_kernel	from 6.12.1 before 6.12.64; from 6.13 before 6.18.4; 6.12; 6.19; 6.19; 6.19; 6.19; 6.19; and 3 more ranges	NVD

References

References

https://git.kernel.org/stable/c/1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66	patch
https://git.kernel.org/stable/c/787515ccb2292f82eb0876993129154629a49651	patch
https://git.kernel.org/stable/c/1adaea51c61b52e24e7ab38f7d3eba023b2d050d	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.