net: ipv6: flowlabel: defer exclusive option free until RCU teardown (Linux Linux)

CVE-2026-31680
HIGH 7.8

En bref

Source
NVD
EPSS
EPSS 0.16 % · centile 6 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

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.

Faiblesses (CWE)

  • CWE-416 — Utilisation après libération

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected d3aedd5ebd4b0b925b0bcda548066803e1318499 < 4b6798024f7b2d535f3db1002c760143cdbd1bd3 ; affected d3aedd5ebd4b0b925b0bcda548066803e1318499 < 3c54b66c83fb8fcbde8e6a7bf90b65856e39f827 ; affected d3aedd5ebd4b0b925b0bcda548066803e1318499 < 5a6b15f861b7c1304949e3350d23490a5fe429fd ; affected d3aedd5ebd4b0b925b0bcda548066803e1318499 < 6c7fbdb8ffde6413640de7cfbd7c976c353e89f8 ; affected d3aedd5ebd4b0b925b0bcda548066803e1318499 < 8027964931785cb73d520ac70a342a3dc16c249b ; affected d3aedd5ebd4b0b925b0bcda548066803e1318499 < 414726b69921fe6355ae453f5b35e68dd078342a
Linux · Linuxaffected 3.9 ; unaffected 0 < 3.9 ; unaffected 5.10.253 ≤ 5.10.* ; unaffected 5.15.203 ≤ 5.15.* ; unaffected 6.1.168 ≤ 6.1.* ; unaffected 6.6.134 ≤ 6.6.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD