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Review reviewHigh

CVE-2026-63968

Linux

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->fib...

CVSS
7.5
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.20
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 7.5

Vulnerability overview

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->fib...

Affected product and versions

Product
Linux
Affected versions
>= d0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2 < 3948a7d92f7678e89e1776bb2d169afcad63b1ae, >= 52da02521ede55fb86546c3fffd9377b3261b91f < c87cd3cb309634bc8f50a54e2079424f219ac21f, >= 34a949e7a0869dfa31a40416d2a56973fae1807b < 0f7b73c3452635de83b8711b31abdda8e49aad7b, >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < ab9a10969a907b472a0196d999c08ff7144172e3, >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9b9d5bd6e3d4c9cecab5407604b690684b2532d2, >= d9ccb18f83ea2bb654289b6ecf014fd267cc988b < 9c7da87c2dc860bb17ca1ece942495d28b1ce3b9, >= 11edcd026012ac18acee0f1514db3ed1b160fc6f, >= 6.1.128 < 6.1.176, >= 6.6.75 < 6.6.143, >= 6.12.2 < 6.12.93, >= 6.11.11 < 6.12, >= 6.13
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
Not available