{"id":"CVE-2025-39773","summary":"net: bridge: fix soft lockup in br_multicast_query_expired()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: fix soft lockup in br_multicast_query_expired()\n\nWhen set multicast_query_interval to a large value, the local variable\n'time' in br_multicast_send_query() may overflow. If the time is smaller\nthan jiffies, the timer will expire immediately, and then call mod_timer()\nagain, which creates a loop and may trigger the following soft lockup\nissue.\n\n  watchdog: BUG: soft lockup - CPU#1 stuck for 221s! [rb_consumer:66]\n  CPU: 1 UID: 0 PID: 66 Comm: rb_consumer Not tainted 6.16.0+ #259 PREEMPT(none)\n  Call Trace:\n   \u003cIRQ\u003e\n   __netdev_alloc_skb+0x2e/0x3a0\n   br_ip6_multicast_alloc_query+0x212/0x1b70\n   __br_multicast_send_query+0x376/0xac0\n   br_multicast_send_query+0x299/0x510\n   br_multicast_query_expired.constprop.0+0x16d/0x1b0\n   call_timer_fn+0x3b/0x2a0\n   __run_timers+0x619/0x950\n   run_timer_softirq+0x11c/0x220\n   handle_softirqs+0x18e/0x560\n   __irq_exit_rcu+0x158/0x1a0\n   sysvec_apic_timer_interrupt+0x76/0x90\n   \u003c/IRQ\u003e\n\nThis issue can be reproduced with:\n  ip link add br0 type bridge\n  echo 1 \u003e /sys/class/net/br0/bridge/multicast_querier\n  echo 0xffffffffffffffff \u003e\n  \t/sys/class/net/br0/bridge/multicast_query_interval\n  ip link set dev br0 up\n\nThe multicast_startup_query_interval can also cause this issue. Similar to\nthe commit 99b40610956a (\"net: bridge: mcast: add and enforce query\ninterval minimum\"), add check for the query interval maximum to fix this\nissue.","modified":"2026-04-02T12:48:08.901486Z","published":"2025-09-11T16:56:26.820Z","related":["SUSE-SU-2025:03600-1","SUSE-SU-2025:03601-1","SUSE-SU-2025:03602-1","SUSE-SU-2025:03614-1","SUSE-SU-2025:03633-1","SUSE-SU-2025:03634-1","SUSE-SU-2025:20851-1","SUSE-SU-2025:20861-1","SUSE-SU-2025:20870-1","SUSE-SU-2025:20898-1","SUSE-SU-2025:21074-1","SUSE-SU-2025:21139-1","SUSE-SU-2025:21179-1","SUSE-SU-2025:3725-1","SUSE-SU-2025:3751-1","openSUSE-SU-2025:20081-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39773.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/34171b9e53bd1dc264f5556579f2b04f04435c73"},{"type":"WEB","url":"https://git.kernel.org/stable/c/43e281fde5e76a866a4d10780c35023f16c0e432"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5bf5fce8a0c2a70d063af778fdb5b27238174cdd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/96476b043efb86a94f2badd260f7f99c97bd5893"},{"type":"WEB","url":"https://git.kernel.org/stable/c/bdb19cd0de739870bb3494c815138b9dc30875c4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/d1547bf460baec718b3398365f8de33d25c5f36f"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39773.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-39773"},{"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":"d902eee43f1951b358d7347d9165c6af21cf7b1b"},{"fixed":"34171b9e53bd1dc264f5556579f2b04f04435c73"},{"fixed":"43e281fde5e76a866a4d10780c35023f16c0e432"},{"fixed":"96476b043efb86a94f2badd260f7f99c97bd5893"},{"fixed":"bdb19cd0de739870bb3494c815138b9dc30875c4"},{"fixed":"5bf5fce8a0c2a70d063af778fdb5b27238174cdd"},{"fixed":"d1547bf460baec718b3398365f8de33d25c5f36f"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39773.json"}}],"schema_version":"1.7.5"}