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CVE-2026-23124

ipv6: annotate data-race in ndisc_router_discovery()

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.15.199, 6.1.162, 6.6.122, 6.12.68, 6.18.8
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

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

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 · fixed in 4630897eb1a039b5d7b737b8dc9521d9d4b568b5; From 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 · fixed in 2619499169fb1c2ac4974b0f2d87767fb543582b; From 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 · fixed in fad8f4ff7928f4d52a062ffdcffa484989c79c47; From 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 · fixed in 2a2b9d25f801afecf2f83cacce98afa8fd73e3c9; From 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 · fixed in e3c1040252e598f7b4e33a42dc7c38519bc22428; From 49b99da2c9ce13ffcd93fe3a0f5670791c1d76f7 · fixed in 9a063f96d87efc3a6cc667f8de096a3d38d74bb5

  • Linux Linux

    5.15

  • KernelLinux

    From 5.15.0 · fixed in 5.15.199; From 5.16.0 · fixed in 6.1.162; From 6.2.0 · fixed in 6.6.122; From 6.7.0 · fixed in 6.12.68; From 6.13.0 · fixed in 6.18.8

References 6

git.kernel.org