{"id":"CVE-2026-63968","title":"ipv6: fix possible infinite loop in fib6_select_path()","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix possible infinite loop in fib6_select_path()\n\nFound while auditing the same pattern Sashiko reported in\nrt6_fill_node() [1]. Apply the same fix as\ncommit f8d8…","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= d0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2 < 3948a7d92f7678e89e1776bb2d169afcad63b1ae","Linux >= 52da02521ede55fb86546c3fffd9377b3261b91f < c87cd3cb309634bc8f50a54e2079424f219ac21f","Linux >= 34a949e7a0869dfa31a40416d2a56973fae1807b < 0f7b73c3452635de83b8711b31abdda8e49aad7b","Linux >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < ab9a10969a907b472a0196d999c08ff7144172e3","Linux >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9b9d5bd6e3d4c9cecab5407604b690684b2532d2","Linux >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9c7da87c2dc860bb17ca1ece942495d28b1ce3b9","Linux 11edcd026012ac18acee0f1514db3ed1b160fc6f","Linux >= 6.1.128 < 6.1.176","Linux >= 6.6.75 < 6.6.143","Linux >= 6.12.2 < 6.12.93","Linux >= 6.11.11 < 6.12","Linux 6.13"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-10-16T15:34:13.232918Z"},"published":"2026-07-19","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:42:14.683Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-63968","references":[{"url":"https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae"},{"url":"https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f"},{"url":"https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b"},{"url":"https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3"},{"url":"https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2"},{"url":"https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9"}],"tags":["cve.org"],"epss":0.00665,"epssPercentile":0.50775,"ingestedAt":"2026-10-16T17:24:46.784Z","slug":"CVE-2026-63968","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nipv6: fix possible infinite loop in fib6_select_path()\n\nFound while auditing the same pattern Sashiko reported in\nrt6_fill_node() [1]. Apply the same fix as\ncommit f8d8ce1b515a (\"ipv6: fix possible infinite loop in fib6_info_uses_dev()\").\n\nWriters holding tb6_lock can list_del_rcu(&first->fib6_siblings)\nwithout waiting for RCU readers; first->fib6_siblings.next then\nstill points into the old ring and this softirq-side walker never\nreaches &first->fib6_siblings as its terminator. fib6_purge_rt()\nalways WRITE_ONCE()s first->fib6_nsiblings to 0 before\nlist_del_rcu(), so an inside-loop check is a reliable detach signal.\n\n[1] https://sashiko.dev/#/patchset/20260526020227.4857-1-jiayuan.chen%40linux.dev\n\n## Affected\n\n- `Linux >= d0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2 < 3948a7d92f7678e89e1776bb2d169afcad63b1ae`\n- `Linux >= 52da02521ede55fb86546c3fffd9377b3261b91f < c87cd3cb309634bc8f50a54e2079424f219ac21f`\n- `Linux >= 34a949e7a0869dfa31a40416d2a56973fae1807b < 0f7b73c3452635de83b8711b31abdda8e49aad7b`\n- `Linux >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < ab9a10969a907b472a0196d999c08ff7144172e3`\n- `Linux >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9b9d5bd6e3d4c9cecab5407604b690684b2532d2`\n- `Linux >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9c7da87c2dc860bb17ca1ece942495d28b1ce3b9`\n- `Linux 11edcd026012ac18acee0f1514db3ed1b160fc6f`\n- `Linux >= 6.1.128 < 6.1.176`\n- `Linux >= 6.6.75 < 6.6.143`\n- `Linux >= 6.12.2 < 6.12.93`\n- `Linux >= 6.11.11 < 6.12`\n- `Linux 6.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}