CVE-2026-23124ipv6: annotate data-race in ndisc_router_discovery()
- 5.5MediumCVSS base score
- 0.11%Exploitation in 30 daysEPSS · top 99% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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
Timeline
ID reserved
By Linux
- 32 days later
· 32 days later
Published
- 8 months later
· 8 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.11% · top 99% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.5.
Affected products
- affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 – < 4630897eb1a039b5d7b737b8dc9521d9d4b568b5
- affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 – < 2619499169fb1c2ac4974b0f2d87767fb543582b
- affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 – < fad8f4ff7928f4d52a062ffdcffa484989c79c47
- affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 – < 2a2b9d25f801afecf2f83cacce98afa8fd73e3c9
- affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 – < e3c1040252e598f7b4e33a42dc7c38519bc22428
- affected 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 – < 9a063f96d87efc3a6cc667f8de096a3d38d74bb5
- affected 5.15
- unaffected < 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.*
- unaffected 6.18.8 – ≤ 6.18.*
- unaffected 6.19 – ≤ *
References
References6
- https://git.kernel.org/stable/c/4630897eb1a039b5d7b737b8dc9521d9d4b568b5 (opens in a new tab)
- https://git.kernel.org/stable/c/2619499169fb1c2ac4974b0f2d87767fb543582b (opens in a new tab)
- https://git.kernel.org/stable/c/fad8f4ff7928f4d52a062ffdcffa484989c79c47 (opens in a new tab)
- https://git.kernel.org/stable/c/2a2b9d25f801afecf2f83cacce98afa8fd73e3c9 (opens in a new tab)
- https://git.kernel.org/stable/c/e3c1040252e598f7b4e33a42dc7c38519bc22428 (opens in a new tab)
- https://git.kernel.org/stable/c/9a063f96d87efc3a6cc667f8de096a3d38d74bb5 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-5912 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-23124)Record last updated .