{"id":"CVE-2025-71080","summary":"ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT\n\nOn PREEMPT_RT kernels, after rt6_get_pcpu_route() returns NULL, the\ncurrent task can be preempted. Another task running on the same CPU\nmay then execute rt6_make_pcpu_route() and successfully install a\npcpu_rt entry. When the first task resumes execution, its cmpxchg()\nin rt6_make_pcpu_route() will fail because rt6i_pcpu is no longer\nNULL, triggering the BUG_ON(prev). It's easy to reproduce it by adding\nmdelay() after rt6_get_pcpu_route().\n\nUsing preempt_disable/enable is not appropriate here because\nip6_rt_pcpu_alloc() may sleep.\n\nFix this by handling the cmpxchg() failure gracefully on PREEMPT_RT:\nfree our allocation and return the existing pcpu_rt installed by\nanother task. The BUG_ON is replaced by WARN_ON_ONCE for non-PREEMPT_RT\nkernels where such races should not occur.","modified":"2026-03-20T12:46:35.475982Z","published":"2026-01-13T15:34:44.832Z","related":["SUSE-SU-2026:0447-1","SUSE-SU-2026:0472-1","SUSE-SU-2026:0587-1","SUSE-SU-2026:20555-1","SUSE-SU-2026:20599-1","SUSE-SU-2026:20615-1","openSUSE-SU-2026:20287-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71080.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1adaea51c61b52e24e7ab38f7d3eba023b2d050d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66"},{"type":"WEB","url":"https://git.kernel.org/stable/c/787515ccb2292f82eb0876993129154629a49651"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/71xxx/CVE-2025-71080.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-71080"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d2d6422f8bd17c6bb205133e290625a564194496"},{"fixed":"1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66"},{"fixed":"787515ccb2292f82eb0876993129154629a49651"},{"fixed":"1adaea51c61b52e24e7ab38f7d3eba023b2d050d"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-71080.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.12.64"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-71080.json"}}],"schema_version":"1.7.5"}