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VulnerabilityPublished Updated

CVE-2024-26631: Linux kernel · ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work idev->mc_ifc_count can be

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1057.63~20.04.1 : patch Linux kernel soon.

Data as of 12 Nov 2026, 18:50 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 5.15.0-1057.63~20.04.1, 5.15.0-1060.69~20.04.1, 5.15.0-1055.63~20.04.1 +38
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Mar 2024

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 12 Nov 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
Ubuntu Pro Realtime 24.04 LTSlinux-raspi-realtimepkg:deb/ubuntu/linux-raspi-realtime?arch=source&distro=realtime/nobleOther threatsAffected
  • <6.8.0-2001.1
Fixed in
  • 6.8.0-2001.1
Ubuntu 22.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=jammyOther threatsAffected
  • <5.15.0-102.112
Fixed in
  • 5.15.0-102.112
Ubuntu 22.04 LTSlinux-allwinner-5.19pkg:deb/ubuntu/linux-allwinner-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1007.7~22.04.1 – 5.19.0-1015.15~22.04.1
8 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=jammyOther threatsAffected
  • <5.15.0-1057.63
Fixed in
  • 5.15.0-1057.63
Ubuntu 22.04 LTSlinux-aws-5.19pkg:deb/ubuntu/linux-aws-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1019.20~22.04.1 – 5.19.0-1029.30~22.04.1
10 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-aws-6.2pkg:deb/ubuntu/linux-aws-6.2?arch=source&distro=jammyOther threatsAffected
  • 6.2.0-1005.5~22.04.1 – 6.2.0-1018.18~22.04.1
14 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: fix data-race in ipv6_mc_down / mld_ifc_work idev->mc_ifc_count can be written over without proper locking. Originally found by syzbot [1], fix this issue by encapsulating calls to mld_ifc_stop_work() (and mld_gq_stop_work() for good measure) with mutex_lock() and mutex_unlock() accordingly as these functions should only be called with mc_lock per their declarations. [1] BUG: KCSAN: data-race in ipv6_mc_down / mld_ifc_work write to 0xffff88813a80c832 of 1 bytes by task 3771 on cpu 0: mld_ifc_stop_work net/ipv6/mcast.c:1080 [inline] ipv6_mc_down+0x10a/0x280 net/ipv6/mcast.c:2725 addrconf_ifdown+0xe32/0xf10 net/ipv6/addrconf.c:3949 addrconf_notify+0x310/0x980 notifier_call_chain kernel/notifier.c:93 [inline] raw_notifier_call_chain+0x6b/0x1c0 kernel/notifier.c:461 __dev_notify_flags+0x205/0x3d0 dev_change_flags+0xab/0xd0 net/core/dev.c:8685 do_setlink+0x9f6/0x2430 net/core/rtnetlink.c:2916 rtnl_group_changelink net/core/rtnetlink.c:3458 [inline] __rtnl_newlink net/core/rtnetlink.c:3717 [inline] rtnl_newlink+0xbb3/0x1670 net/core/rtnetlink.c:3754 rtnetlink_rcv_msg+0x807/0x8c0 net/core/rtnetlink.c:6558 netlink_rcv_skb+0x126/0x220 net/netlink/af_netlink.c:2545 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:6576 netlink_unicast_kernel net/netlink/af_netlink.c:1342 [inline] netlink_unicast+0x589/0x650 net/netlink/af_netlink.c:1368 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1910 ... write to 0xffff88813a80c832 of 1 bytes by task 22 on cpu 1: mld_ifc_work+0x54c/0x7b0 net/ipv6/mcast.c:2653 process_one_work kernel/workqueue.c:2627 [inline] process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2700 worker_thread+0x525/0x730 kernel/workqueue.c:2781 ...

References

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