Vulnerability in Linux

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

EPSS: 0.007 (49.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

  • Linux — versions d0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2, 52da02521ede55fb86546c3fffd9377b3261b91f, 34a949e7a0869dfa31a40416d2a56973fae1807b

References

Frequently asked questions

What is CVE-2026-63968?
CVE-2026-63968 is a high-severity vulnerability in Linux. CVSS score: 7.5/10. Published 2026-07-19.
How severe is CVE-2026-63968?
High severity. CVSS v3 base score is 7.5 out of 10.