CVE-2026-63968

High

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

SeverityHigh
CVSS7.5
Exploit probability—
ProductLinux Kernel
PublishedJul 19, 2026
First seenJul 19, 2026
Weakness typeCWE-835CWE-835

How to fix

Update
  • linux linux_kernel6.1.176, 6.6.143, 6.12, 6.12.93, 6.18.35, 7.0.12 or later

Affected products

ProductAffected versionsFixed in
linux linux_kernel6.1.128 ≤ v < 6.1.176, 6.6.75 ≤ v < 6.6.143, 6.11.11 ≤ v < 6.12, 6.12.2 ≤ v < 6.12.93, 6.13 ≤ v < 6.18.35, 6.19 ≤ v < 7.0.12, 7.16.1.176, 6.6.143, 6.12, 6.12.93, 6.18.35, 7.0.12

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