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
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 18 Mar 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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.
Patches and advisories
- ubuntu.com/security/notices/USN-6725-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6725-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-4 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu Pro Realtime 24.04 LTSlinux-raspi-realtimepkg:deb/ubuntu/linux-raspi-realtime?arch=source&distro=realtime/nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSlinux-allwinner-5.19pkg:deb/ubuntu/linux-allwinner-5.19?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSlinux-aws-5.19pkg:deb/ubuntu/linux-aws-5.19?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSlinux-aws-6.2pkg:deb/ubuntu/linux-aws-6.2?arch=source&distro=jammyOther threats | Affected
| 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
- ubuntu.com/security/CVE-2024-26631 (opens in a new tab)
- git.kernel.org/linus/2e7ef287f07c74985f1bf2858bedc62bd9ebf155 (opens in a new tab)
- git.kernel.org/stable/c/62b3387beef11738eb6ce667601a28fa089fa02c (opens in a new tab)
- git.kernel.org/stable/c/380540bb06bb1d1b12bdc947d1b8f56cda6b5663 (opens in a new tab)
- git.kernel.org/stable/c/3cc283fd16fba72e2cefe3a6f48d7a36b0438900 (opens in a new tab)
- git.kernel.org/stable/c/3bb5849675ae1d592929798a2b37ea450879c855 (opens in a new tab)
- git.kernel.org/stable/c/2e7ef287f07c74985f1bf2858bedc62bd9ebf155 (opens in a new tab)
- ubuntu.com/security/notices/USN-6725-1 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-26631 (opens in a new tab)
- ubuntu.com/security/notices/USN-6725-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-6818-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-6819-4 (opens in a new tab)