GHSA-C2HG-PGQH-6WP2
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31In 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
{
"affected": [],
"aliases": [
"CVE-2026-63968"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:15Z",
"severity": "HIGH"
},
"details": "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(\u0026first-\u003efib6_siblings)\nwithout waiting for RCU readers; first-\u003efib6_siblings.next then\nstill points into the old ring and this softirq-side walker never\nreaches \u0026first-\u003efib6_siblings as its terminator. fib6_purge_rt()\nalways WRITE_ONCE()s first-\u003efib6_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",
"id": "GHSA-c2hg-pgqh-6wp2",
"modified": "2026-07-20T15:31:53Z",
"published": "2026-07-19T18:31:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63968"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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