CVE-2026-63968
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix possible infinite loop in fib6_select_path() Found while auditing the same pattern Sashiko reported in rt6_fill_node() [1]. Apply the same fix as commit f8d8ce1b515a ("ipv6: fix possible infinite loop in fib6_info_uses_dev()"). Writers holding tb6_lock can list_del_rcu(&first->fib6_siblings) without waiting for RCU readers; first->fib6_siblings.next then still points into the old ring and this softirq-side walker never reaches &first->fib6_siblings as its terminator. fib6_purge_rt() always WRITE_ONCE()s first->fib6_nsiblings to 0 before list_del_rcu(), so an inside-loop check is a reliable detach signal. [1] https://sashiko.dev/#/patchset/20260526020227.4857-1-jiayuan.chen%40linux.dev
Severity
HIGH
CVSS score
7.5
(v3.1)
Vulnerability status
Undergoing Analysis
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-07-19 16:17:15.830000
Last modified
2026-10-19 21:17:14.327000
View original CVE JSON
{
"id": "CVE-2026-63968",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-07-19T16:17:15.830",
"lastModified": "2026-10-19T21:17:14.327",
"vulnStatus": "Undergoing Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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 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"
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"net/ipv6/route.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "d0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2",
"lessThan": "3948a7d92f7678e89e1776bb2d169afcad63b1ae",
"versionType": "git",
"status": "affected"
},
{
"version": "52da02521ede55fb86546c3fffd9377b3261b91f",
"lessThan": "c87cd3cb309634bc8f50a54e2079424f219ac21f",
"versionType": "git",
"status": "affected"
},
{
"version": "34a949e7a0869dfa31a40416d2a56973fae1807b",
"lessThan": "0f7b73c3452635de83b8711b31abdda8e49aad7b",
"versionType": "git",
"status": "affected"
},
{
"version": "d9ccb18f83ea2bb654289b6ecf014fd267cc988b",
"lessThan": "ab9a10969a907b472a0196d999c08ff7144172e3",
"versionType": "git",
"status": "affected"
},
{
"version": "d9ccb18f83ea2bb654289b6ecf014fd267cc988b",
"lessThan": "9b9d5bd6e3d4c9cecab5407604b690684b2532d2",
"versionType": "git",
"status": "affected"
},
{
"version": "d9ccb18f83ea2bb654289b6ecf014fd267cc988b",
"lessThan": "9c7da87c2dc860bb17ca1ece942495d28b1ce3b9",
"versionType": "git",
"status": "affected"
},
{
"version": "11edcd026012ac18acee0f1514db3ed1b160fc6f",
"versionType": "git",
"status": "affected"
},
{
"version": "6.1.128",
"lessThan": "6.1.176",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.6.75",
"lessThan": "6.6.143",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.12.2",
"lessThan": "6.12.93",
"versionType": "semver",
"status": "affected"
},
{
"version": "6.11.11",
"lessThan": "6.12",
"versionType": "semver",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"net/ipv6/route.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "6.13",
"status": "affected"
},
{
"version": "0",
"lessThan": "6.13",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.176",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.143",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.93",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.35",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.0.12",
"lessThanOrEqual": "7.0.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.1",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"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",
"attackVector": "NETWORK",
"attackComplexity": "LOW",
"privilegesRequired": "NONE",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 3.9,
"impactScore": 3.6
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-10-16T15:34:13.232918Z",
"id": "CVE-2026-63968",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-835"
}
]
}
],
"references": [
{
"url": "https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}