{"id":"CVE-2026-74398","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-74398","summary":"ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD\n\naddrconf_dad_failure() transitions ifp->state from DAD to POSTDAD\nvia addrconf_dad_end(), which drops ifp->lock on return.  The lock\nis re-acquired after net_info_ratelimited().  A concurrent\nipv6_del_addr() can take the lock in that window, set ifp->state\nto DEAD and run list_del_rcu(&ifp->if_list).\n\naddrconf_dad_failure() then overwrites DEAD with ERRDAD at errdad:\nand schedules a new dad_work.  The work calls ipv6_del_addr()\nagain, hitting the already-poisoned list entry:\n\n  general protection fault: 0000 [#1] SMP NOPTI\n  CPU: 4 PID: 217 Comm: kworker/4:1\n  Workqueue: ipv6_addrconf addrconf_dad_work\n  RIP: 0010:ipv6_del_addr+0xe9/0x280\n  RAX: dead000000000122\n  Call Trace:\n   addrconf_dad_stop+0x113/0x140\n   addrconf_dad_work+0x28c/0x430\n   process_one_work+0x1eb/0x3b0\n   worker_thread+0x4d/0x400\n   kthread+0x104/0x140\n   ret_from_fork+0x35/0x40\n\nFold the addrconf_dad_end() logic into addrconf_dad_failure() under\na single ifp->lock critical section.  The STABLE_PRIVACY branch\ntemporarily drops ifp->lock around address regeneration, so at\nlock_errdad: verify the state is still POSTDAD before transitioning\nto ERRDAD; bail out otherwise to avoid overwriting a state set by\nanother path while the lock was released.","published":"2026-08-15T05:59:10.113Z","modified":"2026-08-18T03:56:47.179992224Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"5.10.261"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb"},{"type":"WEB","url":"https://git.kernel.org/stable/c/47b05836705b63dab93d9ac7c69a3a507375ef80"},{"type":"WEB","url":"https://git.kernel.org/stable/c/627ac78f2741e2ebd2225e2e953b6964a8a9182f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/875c284c0f98b042bb97abad460f63a24c977f88"},{"type":"WEB","url":"https://git.kernel.org/stable/c/8ed0ce9ea58d677d1bac92614ee5f60f8ea57363"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b61af0268e3d1308c466bf0be5dced844eafc1ef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d21be7d051012c6b572fa4e3334443c250216f7b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e889aa99ad3ed48bb0ddcff6475b17542532d18b"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74398.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74398"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-18T03:56:47.179992224Z"}}