ipv6: annotate data-race in ndisc_router_discovery() (Linux Linux)

CVE-2026-23124
MEDIUM 5.5

At a glance

Source
NVD
EPSS
EPSS 0.10 % · percentile 1 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Modified

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: annotate data-race in ndisc_router_discovery() syzbot found that ndisc_router_discovery() could read and write in6_dev->ra_mtu without holding a lock [1] This looks fine, IFLA_INET6_RA_MTU is best effort. Add READ_ONCE()/WRITE_ONCE() to document the race. Note that we might also reject illegal MTU values (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) in a future patch. [1] BUG: KCSAN: data-race in ndisc_router_discovery / ndisc_router_discovery read to 0xffff888119809c20 of 4 bytes by task 25817 on cpu 1: ndisc_router_discovery+0x151d/0x1c90 net/ipv6/ndisc.c:1558 ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841 icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989 ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79 ... write to 0xffff888119809c20 of 4 bytes by task 25816 on cpu 0: ndisc_router_discovery+0x155a/0x1c90 net/ipv6/ndisc.c:1559 ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841 icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989 ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438 ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489 NF_HOOK include/linux/netfilter.h:318 [inline] ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500 ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590 dst_input include/net/dst.h:474 [inline] ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79 ... value changed: 0x00000000 -> 0xe5400659

Weaknesses (CWE)

  • CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization

References

Scores

VersionScoreVectorScored by
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
Linux · Linuxaffected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 < 4630897eb1a039b5d7b737b8dc9521d9d4b568b5 ; affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 < 2619499169fb1c2ac4974b0f2d87767fb543582b ; affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 < fad8f4ff7928f4d52a062ffdcffa484989c79c47 ; affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 < 2a2b9d25f801afecf2f83cacce98afa8fd73e3c9 ; affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 < e3c1040252e598f7b4e33a42dc7c38519bc22428 ; affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 < 9a063f96d87efc3a6cc667f8de096a3d38d74bb5
Linux · Linuxaffected 5.15 ; unaffected 0 < 5.15 ; unaffected 5.15.199 ≤ 5.15.* ; unaffected 6.1.162 ≤ 6.1.* ; unaffected 6.6.122 ≤ 6.6.* ; unaffected 6.12.68 ≤ 6.12.*

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