CVE-2026-63968
ipv6: fix possible infinite loop in fib6_select_path()
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
INFO
Published Date :
July 19, 2026, 4:17 p.m.
Last Modified :
July 30, 2026, 2:51 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to include the fix.
- Ensure RCU locking mechanisms are correctly implemented.
- Review similar locking patterns in related functions.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-63968.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-63968 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-63968
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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The following list is the news that have been mention
CVE-2026-63968 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-63968 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 20, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jul. 19, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': 'd0ec61c9f3583b76aebdbb271f5c0d3fcccd48b2', 'lessThan': '3948a7d92f7678e89e1776bb2d169afcad63b1ae', 'versionType': 'git'}, {'status': 'affected', 'version': '52da02521ede55fb86546c3fffd9377b3261b91f', 'lessThan': 'c87cd3cb309634bc8f50a54e2079424f219ac21f', 'versionType': 'git'}, {'status': 'affected', 'version': '34a949e7a0869dfa31a40416d2a56973fae1807b', 'lessThan': '0f7b73c3452635de83b8711b31abdda8e49aad7b', 'versionType': 'git'}, {'status': 'affected', 'version': 'd9ccb18f83ea2bb654289b6ecf014fd267cc988b', 'lessThan': 'ab9a10969a907b472a0196d999c08ff7144172e3', 'versionType': 'git'}, {'status': 'affected', 'version': 'd9ccb18f83ea2bb654289b6ecf014fd267cc988b', 'lessThan': '9b9d5bd6e3d4c9cecab5407604b690684b2532d2', 'versionType': 'git'}, {'status': 'affected', 'version': 'd9ccb18f83ea2bb654289b6ecf014fd267cc988b', 'lessThan': '9c7da87c2dc860bb17ca1ece942495d28b1ce3b9', 'versionType': 'git'}, {'status': 'affected', 'version': '11edcd026012ac18acee0f1514db3ed1b160fc6f', 'versionType': 'git'}, {'status': 'affected', 'version': '6.1.128', 'lessThan': '6.1.176', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.6.75', 'lessThan': '6.6.143', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.12.2', 'lessThan': '6.12.93', 'versionType': 'semver'}, {'status': 'affected', 'version': '6.11.11', 'lessThan': '6.12', 'versionType': 'semver'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'unaffected'}, {'repo': 'https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git', 'vendor': 'Linux', 'product': 'Linux', 'versions': [{'status': 'affected', 'version': '6.13'}, {'status': 'unaffected', 'version': '0', 'lessThan': '6.13', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '6.1.176', 'versionType': 'semver', 'lessThanOrEqual': '6.1.*'}, {'status': 'unaffected', 'version': '6.6.143', 'versionType': 'semver', 'lessThanOrEqual': '6.6.*'}, {'status': 'unaffected', 'version': '6.12.93', 'versionType': 'semver', 'lessThanOrEqual': '6.12.*'}, {'status': 'unaffected', 'version': '6.18.35', 'versionType': 'semver', 'lessThanOrEqual': '6.18.*'}, {'status': 'unaffected', 'version': '7.0.12', 'versionType': 'semver', 'lessThanOrEqual': '7.0.*'}, {'status': 'unaffected', 'version': '7.1', 'versionType': 'original_commit_for_fix', 'lessThanOrEqual': '*'}], 'programFiles': ['net/ipv6/route.c'], 'defaultStatus': 'affected'}] Added 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 Added Reference https://git.kernel.org/stable/c/0f7b73c3452635de83b8711b31abdda8e49aad7b Added Reference https://git.kernel.org/stable/c/3948a7d92f7678e89e1776bb2d169afcad63b1ae Added Reference https://git.kernel.org/stable/c/9b9d5bd6e3d4c9cecab5407604b690684b2532d2 Added Reference https://git.kernel.org/stable/c/9c7da87c2dc860bb17ca1ece942495d28b1ce3b9 Added Reference https://git.kernel.org/stable/c/ab9a10969a907b472a0196d999c08ff7144172e3 Added Reference https://git.kernel.org/stable/c/c87cd3cb309634bc8f50a54e2079424f219ac21f