CVE-2026-63968
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
Affected versions
Linux kernel versions
6.1.128,
6.6.75,
6.12.2,
6.11.11,
6.13
and later are affected. Fixed in
6.1.176,
6.6.143,
6.12.93,
6.18.35,
7.0.12,
7.1
and their respective stable series.
References
6 totalFrequently asked questions
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What is CVE-2026-63968?
CVE-2026-63968 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.1.128 onward and has been patched in 6.1.176, 6.6.143, 6.12.93 and others. CVE-2026-63968 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-63968?
Yes — CVE-2026-63968 has been patched. Fixed versions include 6.1.176, 6.6.143, 6.12.93 and others. If you are running Linux kernel 6.1.128 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-63968 actively exploited?
No — CVE-2026-63968 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.