{"id":"CVE-2026-74398","title":"ipv6: addrconf: bail out of dad_failure when state is no longer POSTDAD","summary":"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…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 47b05836705b63dab93d9ac7c69a3a507375ef80","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < d21be7d051012c6b572fa4e3334443c250216f7b","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 875c284c0f98b042bb97abad460f63a24c977f88","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 8ed0ce9ea58d677d1bac92614ee5f60f8ea57363","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < b61af0268e3d1308c466bf0be5dced844eafc1ef","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < e889aa99ad3ed48bb0ddcff6475b17542532d18b","Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 627ac78f2741e2ebd2225e2e953b6964a8a9182f","Linux 835b474b8f70fa68d68abffad37378e92f661802","Linux >= 3.10.105 < 3.11","Linux 3.14"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:55:29.102774Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:05:41.331Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-74398","references":[{"url":"https://git.kernel.org/stable/c/47b05836705b63dab93d9ac7c69a3a507375ef80"},{"url":"https://git.kernel.org/stable/c/d21be7d051012c6b572fa4e3334443c250216f7b"},{"url":"https://git.kernel.org/stable/c/875c284c0f98b042bb97abad460f63a24c977f88"},{"url":"https://git.kernel.org/stable/c/8ed0ce9ea58d677d1bac92614ee5f60f8ea57363"},{"url":"https://git.kernel.org/stable/c/3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb"},{"url":"https://git.kernel.org/stable/c/b61af0268e3d1308c466bf0be5dced844eafc1ef"},{"url":"https://git.kernel.org/stable/c/e889aa99ad3ed48bb0ddcff6475b17542532d18b"},{"url":"https://git.kernel.org/stable/c/627ac78f2741e2ebd2225e2e953b6964a8a9182f"}],"tags":["cve.org"],"epss":0.00514,"epssPercentile":0.42496,"ingestedAt":"2026-10-16T19:46:24.368Z","slug":"CVE-2026-74398","body":"## Overview\n\nIn 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.\n\n## Affected\n\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 47b05836705b63dab93d9ac7c69a3a507375ef80`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < d21be7d051012c6b572fa4e3334443c250216f7b`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 875c284c0f98b042bb97abad460f63a24c977f88`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 8ed0ce9ea58d677d1bac92614ee5f60f8ea57363`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 3bdc86d89fd6c6523753fa6f42fcfaf30ee699cb`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < b61af0268e3d1308c466bf0be5dced844eafc1ef`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < e889aa99ad3ed48bb0ddcff6475b17542532d18b`\n- `Linux >= c15b1ccadb323ea50023e8f1cca2954129a62b51 < 627ac78f2741e2ebd2225e2e953b6964a8a9182f`\n- `Linux 835b474b8f70fa68d68abffad37378e92f661802`\n- `Linux >= 3.10.105 < 3.11`\n- `Linux 3.14`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}