{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-71080","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-01-13T15:30:19.648Z","datePublished":"2026-01-13T15:34:44.832Z","dateUpdated":"2026-08-05T12:11:55.485Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:11:55.485Z"},"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - Unauthenticated IPv6 packets reach ip6_route_input() and ip6_pol_route() before transport delivery or authentication, exposing the vulnerable per-CPU route creation path to a remote peer.\nAC:L - In a reasonable multi-queue or threaded-network PREEMPT_RT deployment, concurrent attacker-driven packet streams can exercise both sides of the short empty-slot race repeatedly. No memory-layout guess or inherently uncontrollable condition is required.\nPR:N - The inbound IPv6 routing path performs no capability or authentication check before reaching the vulnerable code.\nUI:N - No victim action is required; processing attacker-generated IPv6 traffic triggers route lookup automatically.\nS:U - The resulting kernel failure affects the same host and security authority in which packet processing occurs, without crossing a virtualization or sandbox boundary.\nC:N - The failed cmpxchg only detects an already-installed valid route and immediately reaches BUG_ON; it provides no memory disclosure or read primitive.\nI:N - The atomic installation fails without overwriting the existing pointer, and there is no use-after-free, out-of-bounds write, or other attacker-controlled modification.\nA:H - BUG_ON executes while bottom halves are disabled and raises a fatal invalid-opcode oops, which can directly produce a kernel panic and complete system outage."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/route.c"],"versions":[{"version":"d2d6422f8bd17c6bb205133e290625a564194496","lessThan":"1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66","status":"affected","versionType":"git"},{"version":"d2d6422f8bd17c6bb205133e290625a564194496","lessThan":"787515ccb2292f82eb0876993129154629a49651","status":"affected","versionType":"git"},{"version":"d2d6422f8bd17c6bb205133e290625a564194496","lessThan":"1adaea51c61b52e24e7ab38f7d3eba023b2d050d","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/ipv6/route.c"],"versions":[{"version":"6.12","status":"affected"},{"version":"0","lessThan":"6.12","status":"unaffected","versionType":"semver"},{"version":"6.12.64","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.4","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"6.19","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.64"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.18.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.19"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/1dc33ad0867325f8d2c6d7b2a6f542d4f3121f66"},{"url":"https://git.kernel.org/stable/c/787515ccb2292f82eb0876993129154629a49651"},{"url":"https://git.kernel.org/stable/c/1adaea51c61b52e24e7ab38f7d3eba023b2d050d"}],"title":"ipv6: fix a BUG in rt6_get_pcpu_route() under PREEMPT_RT","x_generator":{"engine":"bippy-1.2.0"}}}}