CVE-2026-23124
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn 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
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisA detailed technical summary for this CVE is being prepared.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 5.15, < 5.15.199>= 5.16, < 6.1.162>= 6.2, < 6.6.122>= 6.7, < 6.12.68>= 6.13, < 6.18.8= 6.19CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.15.1996.1.1626.6.122
Upgrade to the first stable kernel release in your branch that contains the fix: 5.15.199, 6.1.162, 6.6.122, or 6.12.68 (whichever applies to your current branch)
- Identify the currently running kernel version using `uname -r`
- Determine which version range your current kernel falls into (5.15.x, 5.16.x, 6.2.x, 6.7.x, or 6.12.x)
- For 5.15.x: upgrade to kernel version 5.15.199 or later
- For 5.16.x: upgrade to a supported LTS kernel (5.16 is EOL; upgrade to 6.1.162+, 6.6.122+, or 6.12.68+)
- For 6.2.x: upgrade to kernel version 6.6.122 or later
- For 6.7.x: upgrade to kernel version 6.12.68 or later
- For 6.12.x: upgrade to kernel version 6.12.68 or later
- Reboot into the new kernel and verify the fix by checking that the KCSAN warning no longer appears
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-23124 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-23124 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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