CVE Catalog

CVE-2026-63968

HighCVSS 7.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.65%

47th percentile - higher than 47% of all known CVEs

Summary

A vulnerability in the Linux kernel's fib6_select_path() function for IPv6 can cause an infinite loop. The issue arises from a race condition between list_del_rcu() operations on the fib6_siblings list and concurrent softirq readers, preventing the loop terminator from being reached.

Risk Assessment

An infinite loop in the IPv6 processing path can lead to CPU stalls and denial of service (DoS) for IPv6 network traffic, impacting system availability.

Recommendation

Immediately update the Linux kernel to a version containing the fix (commit f8d8ce1b515a or later). Monitor distributions for the patch and apply it as a priority.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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

Vulnerability data from NVD (NIST) · CISA KEV · EPSS