{"id":"CVE-2025-40135","state":"PUBLISHED","title":"ipv6: use RCU in ip6_xmit()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: use RCU in ip6_xmit()\n\nUse RCU in ip6_xmit() in order to use dst_dev_rcu() to prevent\npossible UAF.","publishedAt":"2025-11-12T10:23:23.051Z","updatedAt":"2026-10-30T12:22:50.364Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux 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use RCU in ip6_xmit()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: use RCU in ip6_xmit()\n\nUse RCU in ip6_xmit() in order to use dst_dev_rcu() to prevent\npossible 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Any internet-facing host with an IPv6 TCP listener (or that merely replies with RST) exposes the vulnerable function to unauthenticated remote traffic.\nAC:H - The attacker freely supplies the transmit side of the race by sending TCP/SCTP traffic, but the `dst_dev_put()` side (netdev unregister/link-down, veth teardown, route-exception/pcpu-route destruction) is an operational event they cannot influence from the network, and escalating past a crash requires the freed `net_device`/`inet6_dev` slab object to be reallocated with attacker-useful content. This matches sibling CVE-2025-40158 and CVE-2025-40168 in the same dst_dev_rcu series.\nPR:N - SYNACK and RST generation happen with no credentials, no established session, and no local account on the target — the kernel transmits automatically on packet arrival. 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