{"id":"CVE-2024-44934","summary":"net: bridge: mcast: wait for previous gc cycles when removing port","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mcast: wait for previous gc cycles when removing port\n\nsyzbot hit a use-after-free[1] which is caused because the bridge doesn't\nmake sure that all previous garbage has been collected when removing a\nport. What happens is:\n      CPU 1                   CPU 2\n start gc cycle           remove port\n                         acquire gc lock first\n wait for lock\n                         call br_multicasg_gc() directly\n acquire lock now but    free port\n the port can be freed\n while grp timers still\n running\n\nMake sure all previous gc cycles have finished by using flush_work before\nfreeing the port.\n\n[1]\n  BUG: KASAN: slab-use-after-free in br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861\n  Read of size 8 at addr ffff888071d6d000 by task syz.5.1232/9699\n\n  CPU: 1 PID: 9699 Comm: syz.5.1232 Not tainted 6.10.0-rc5-syzkaller-00021-g24ca36a562d6 #0\n  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024\n  Call Trace:\n   \u003cIRQ\u003e\n   __dump_stack lib/dump_stack.c:88 [inline]\n   dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114\n   print_address_description mm/kasan/report.c:377 [inline]\n   print_report+0xc3/0x620 mm/kasan/report.c:488\n   kasan_report+0xd9/0x110 mm/kasan/report.c:601\n   br_multicast_port_group_expired+0x4c0/0x550 net/bridge/br_multicast.c:861\n   call_timer_fn+0x1a3/0x610 kernel/time/timer.c:1792\n   expire_timers kernel/time/timer.c:1843 [inline]\n   __run_timers+0x74b/0xaf0 kernel/time/timer.c:2417\n   __run_timer_base kernel/time/timer.c:2428 [inline]\n   __run_timer_base kernel/time/timer.c:2421 [inline]\n   run_timer_base+0x111/0x190 kernel/time/timer.c:2437","modified":"2026-04-02T12:18:29.480608Z","published":"2024-08-26T10:11:25.809Z","related":["MGASA-2024-0309","MGASA-2024-0310","SUSE-SU-2025:0117-1","SUSE-SU-2025:0153-1","SUSE-SU-2025:0154-1","SUSE-SU-2025:0201-1","SUSE-SU-2025:0201-2","SUSE-SU-2025:0229-1","SUSE-SU-2025:0289-1","SUSE-SU-2025:20165-1","SUSE-SU-2025:20166-1","SUSE-SU-2025:20248-1","SUSE-SU-2025:20249-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/44xxx/CVE-2024-44934.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0d8b26e10e680c01522d7cc14abe04c3265a928f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/1e16828020c674b3be85f52685e8b80f9008f50f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/92c4ee25208d0f35dafc3213cdf355fbe449e078"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b2f794b168cf560682ff976b255aa6d29d14a658"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e3145ca904fa8dbfd1a5bf0187905bc117b0efce"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/44xxx/CVE-2024-44934.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-44934"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"e12cec65b5546f19217e26aafb8add6e2fadca18"},{"fixed":"1e16828020c674b3be85f52685e8b80f9008f50f"},{"fixed":"0d8b26e10e680c01522d7cc14abe04c3265a928f"},{"fixed":"e3145ca904fa8dbfd1a5bf0187905bc117b0efce"},{"fixed":"b2f794b168cf560682ff976b255aa6d29d14a658"},{"fixed":"92c4ee25208d0f35dafc3213cdf355fbe449e078"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-44934.json"}}],"schema_version":"1.7.5"}