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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-31680 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: net: ipv6: flowlabel: defer exclusive option free until RCU teardown `ip6fl_seq_show()` walks the global flowlabel hash under the seq-file RCU read-side lock and prints `fl->opt->opt_nflen` when an option block is present. Exclusive flowlabels currently free `fl->opt` as soon as `fl->users` drops to zero in `fl_release()`. However, the surrounding `struct ip6_flowlabel` remains visible in the global hash table until later garbage collection removes it and `fl_free_rcu()` finally tears it down. A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that early `kfree()` and dereference freed option state, triggering a crash in `ip6fl_seq_show()`. Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches the lifetime already required for the enclosing flowlabel while readers can still reach it under RCU.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827 kernel.org
https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a kernel.org
https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3 kernel.org
https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4 kernel.org
https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd kernel.org
https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8 kernel.org
https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b kernel.org
https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091 kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-31680
NVD Published Date:
04/25/2026
NVD Last Modified:
04/25/2026
Source:
kernel.org