CVE-2026-23124 (GCVE-0-2026-23124)

Vulnerability from cvelistv5 – Published: 2026-02-14 15:09 – Updated: 2026-02-14 15:09
VLAI?
Title
ipv6: annotate data-race in ndisc_router_discovery()
Summary
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
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 , < 4630897eb1a039b5d7b737b8dc9521d9d4b568b5 (git)
Affected: 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 , < 2619499169fb1c2ac4974b0f2d87767fb543582b (git)
Affected: 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 , < fad8f4ff7928f4d52a062ffdcffa484989c79c47 (git)
Affected: 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 , < 2a2b9d25f801afecf2f83cacce98afa8fd73e3c9 (git)
Affected: 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 , < e3c1040252e598f7b4e33a42dc7c38519bc22428 (git)
Affected: 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 , < 9a063f96d87efc3a6cc667f8de096a3d38d74bb5 (git)
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    Linux Linux Affected: 5.15
Unaffected: 0 , < 5.15 (semver)
Unaffected: 5.15.199 , ≤ 5.15.* (semver)
Unaffected: 6.1.162 , ≤ 6.1.* (semver)
Unaffected: 6.6.122 , ≤ 6.6.* (semver)
Unaffected: 6.12.68 , ≤ 6.12.* (semver)
Unaffected: 6.18.8 , ≤ 6.18.* (semver)
Unaffected: 6.19 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
            "net/ipv6/ndisc.c"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: annotate data-race in ndisc_router_discovery()\n\nsyzbot found that ndisc_router_discovery() could read and write\nin6_dev-\u003era_mtu without holding a lock [1]\n\nThis looks fine, IFLA_INET6_RA_MTU is best effort.\n\nAdd READ_ONCE()/WRITE_ONCE() to document the race.\n\nNote that we might also reject illegal MTU values\n(mtu \u003c IPV6_MIN_MTU || mtu \u003e skb-\u003edev-\u003emtu) in a future patch.\n\n[1]\nBUG: KCSAN: data-race in ndisc_router_discovery / ndisc_router_discovery\n\nread to 0xffff888119809c20 of 4 bytes by task 25817 on cpu 1:\n  ndisc_router_discovery+0x151d/0x1c90 net/ipv6/ndisc.c:1558\n  ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841\n  icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989\n  ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438\n  ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489\n  NF_HOOK include/linux/netfilter.h:318 [inline]\n  ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500\n  ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590\n  dst_input include/net/dst.h:474 [inline]\n  ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79\n...\n\nwrite to 0xffff888119809c20 of 4 bytes by task 25816 on cpu 0:\n  ndisc_router_discovery+0x155a/0x1c90 net/ipv6/ndisc.c:1559\n  ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841\n  icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989\n  ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438\n  ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489\n  NF_HOOK include/linux/netfilter.h:318 [inline]\n  ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500\n  ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590\n  dst_input include/net/dst.h:474 [inline]\n  ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79\n...\n\nvalue changed: 0x00000000 -\u003e 0xe5400659"
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        "shortName": "Linux"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23124",
    "datePublished": "2026-02-14T15:09:54.043Z",
    "dateReserved": "2026-01-13T15:37:45.970Z",
    "dateUpdated": "2026-02-14T15:09:54.043Z",
    "state": "PUBLISHED"
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  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23124\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-02-14T15:16:07.633\",\"lastModified\":\"2026-02-14T15:16:07.633\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nipv6: annotate data-race in ndisc_router_discovery()\\n\\nsyzbot found that ndisc_router_discovery() could read and write\\nin6_dev-\u003era_mtu without holding a lock [1]\\n\\nThis looks fine, IFLA_INET6_RA_MTU is best effort.\\n\\nAdd READ_ONCE()/WRITE_ONCE() to document the race.\\n\\nNote that we might also reject illegal MTU values\\n(mtu \u003c IPV6_MIN_MTU || mtu \u003e skb-\u003edev-\u003emtu) in a future patch.\\n\\n[1]\\nBUG: KCSAN: data-race in ndisc_router_discovery / ndisc_router_discovery\\n\\nread to 0xffff888119809c20 of 4 bytes by task 25817 on cpu 1:\\n  ndisc_router_discovery+0x151d/0x1c90 net/ipv6/ndisc.c:1558\\n  ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841\\n  icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989\\n  ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438\\n  ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489\\n  NF_HOOK include/linux/netfilter.h:318 [inline]\\n  ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500\\n  ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590\\n  dst_input include/net/dst.h:474 [inline]\\n  ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79\\n...\\n\\nwrite to 0xffff888119809c20 of 4 bytes by task 25816 on cpu 0:\\n  ndisc_router_discovery+0x155a/0x1c90 net/ipv6/ndisc.c:1559\\n  ndisc_rcv+0x2ad/0x3d0 net/ipv6/ndisc.c:1841\\n  icmpv6_rcv+0xe5a/0x12f0 net/ipv6/icmp.c:989\\n  ip6_protocol_deliver_rcu+0xb2a/0x10d0 net/ipv6/ip6_input.c:438\\n  ip6_input_finish+0xf0/0x1d0 net/ipv6/ip6_input.c:489\\n  NF_HOOK include/linux/netfilter.h:318 [inline]\\n  ip6_input+0x5e/0x140 net/ipv6/ip6_input.c:500\\n  ip6_mc_input+0x27c/0x470 net/ipv6/ip6_input.c:590\\n  dst_input include/net/dst.h:474 [inline]\\n  ip6_rcv_finish+0x336/0x340 net/ipv6/ip6_input.c:79\\n...\\n\\nvalue changed: 0x00000000 -\u003e 0xe5400659\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/2619499169fb1c2ac4974b0f2d87767fb543582b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2a2b9d25f801afecf2f83cacce98afa8fd73e3c9\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4630897eb1a039b5d7b737b8dc9521d9d4b568b5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9a063f96d87efc3a6cc667f8de096a3d38d74bb5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e3c1040252e598f7b4e33a42dc7c38519bc22428\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fad8f4ff7928f4d52a062ffdcffa484989c79c47\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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