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

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
Linux Linux unaffected
Version Status Constraints
49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 affected < 4630897eb1a039b5d7b737b8dc9521d9d4b568b5
49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 affected < 2619499169fb1c2ac4974b0f2d87767fb543582b
49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 affected < fad8f4ff7928f4d52a062ffdcffa484989c79c47
49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 affected < 2a2b9d25f801afecf2f83cacce98afa8fd73e3c9
49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 affected < e3c1040252e598f7b4e33a42dc7c38519bc22428
49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 affected < 9a063f96d87efc3a6cc667f8de096a3d38d74bb5
Linux Linux affected
Version Status Constraints
5.15 affected —
0 unaffected < 5.15
5.15.199 unaffected ≤ 5.15.*
6.1.162 unaffected ≤ 6.1.*
6.6.122 unaffected ≤ 6.6.*
6.12.68 unaffected ≤ 6.12.*
6.18.8 unaffected ≤ 6.18.*
6.19 unaffected ≤ *

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References
Link Providers
https://git.kernel.org/stable/c/2619499169fb1c2ac4974b0f2d87767fb543582b cve-icon cve-icon
https://git.kernel.org/stable/c/2a2b9d25f801afecf2f83cacce98afa8fd73e3c9 cve-icon cve-icon
https://git.kernel.org/stable/c/4630897eb1a039b5d7b737b8dc9521d9d4b568b5 cve-icon cve-icon
https://git.kernel.org/stable/c/9a063f96d87efc3a6cc667f8de096a3d38d74bb5 cve-icon cve-icon
https://git.kernel.org/stable/c/e3c1040252e598f7b4e33a42dc7c38519bc22428 cve-icon cve-icon
https://git.kernel.org/stable/c/fad8f4ff7928f4d52a062ffdcffa484989c79c47 cve-icon cve-icon
History

Sat, 14 Feb 2026 15:15:00 +0000

Type Values Removed Values Added
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
Title ipv6: annotate data-race in ndisc_router_discovery()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-02-14T15:09:54.043Z

Reserved: 2026-01-13T15:37:45.970Z

Link: CVE-2026-23124

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-02-14T15:16:07.633

Modified: 2026-02-14T15:16:07.633

Link: CVE-2026-23124

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses

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