CVE-2024-44934: Linux kernel · net: bridge: mcast: wait for previous gc cycles when removing port
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1072.78~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 23:28 UTC
- Patch
- Available – fixed in 5.15.0-1072.78~20.04.1, 5.15.0-1078.87~20.04.1, 5.15.0-1071.79~20.04.1 +52
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 26 Aug 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Patches and advisories
- ubuntu.com/security/notices/USN-7100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7123-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7144-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7155-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7156-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7194-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7196-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-gkeoppkg:deb/ubuntu/linux-gkeop?arch=source&distro=nobleOther 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: net: bridge: mcast: wait for previous gc cycles when removing port syzbot hit a use-after-free[1] which is caused because the bridge doesn't make sure that all previous garbage has been collected when removing a port. What happens is: CPU 1 CPU 2 start gc cycle remove port acquire gc lock first wait for lock call br_multicasg_gc() directly acquire lock now but free port the port can be freed while grp timers still running Make sure all previous gc cycles have finished by using flush_work before freeing the port. [1] BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699 CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861 call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792 expire_timers kernel/time/timer.c:1843 [inline] __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437
References
- ubuntu.com/security/CVE-2024-44934 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2024-44934 (opens in a new tab)
- git.kernel.org/linus/92c4ee25208d0f35dafc3213cdf355fbe449e078 (opens in a new tab)
- git.kernel.org/stable/c/1e16828020c674b3be85f52685e8b80f9008f50f (opens in a new tab)
- git.kernel.org/stable/c/0d8b26e10e680c01522d7cc14abe04c3265a928f (opens in a new tab)
- git.kernel.org/stable/c/e3145ca904fa8dbfd1a5bf0187905bc117b0efce (opens in a new tab)
- git.kernel.org/stable/c/b2f794b168cf560682ff976b255aa6d29d14a658 (opens in a new tab)
- git.kernel.org/stable/c/92c4ee25208d0f35dafc3213cdf355fbe449e078 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7100-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7123-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7144-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7155-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7156-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7154-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7194-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7196-1 (opens in a new tab)