{"id":"CVE-2025-39773","state":"PUBLISHED","title":"net: bridge: fix soft lockup in br_multicast_query_expired()","description":"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   <IRQ>\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   </IRQ>\n\nThis issue can be reproduced with:\n  ip link add br0 type bridge\n  echo 1 > /sys/class/net/br0/bridge/multicast_querier\n  echo 0xffffffffffffffff >\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.","publishedAt":"2025-09-11T16:56:26.820Z","updatedAt":"2026-10-15T01:08:16.402Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d902eee43f1951b358d7347d9165c6af21cf7b1b","status":"affected","lessThan":"34171b9e53bd1dc264f5556579f2b04f04435c73","versionType":"git"},{"version":"d902eee43f1951b358d7347d9165c6af21cf7b1b","status":"affected","lessThan":"43e281fde5e76a866a4d10780c35023f16c0e432","versionType":"git"},{"version":"d902eee43f1951b358d7347d9165c6af21cf7b1b","status":"affected","lessThan":"96476b043efb86a94f2badd260f7f99c97bd5893","versionType":"git"},{"version":"d902eee43f1951b358d7347d9165c6af21cf7b1b","status":"affected","lessThan":"bdb19cd0de739870bb3494c815138b9dc30875c4","versionType":"git"},{"version":"d902eee43f1951b358d7347d9165c6af21cf7b1b","status":"affected","lessThan":"5bf5fce8a0c2a70d063af778fdb5b27238174cdd","versionType":"git"},{"version":"d902eee43f1951b358d7347d9165c6af21cf7b1b","status":"affected","lessThan":"d1547bf460baec718b3398365f8de33d25c5f36f","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bridge/br_multicast.c","net/bridge/br_private.h"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.34","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.34","versionType":"semver"},{"version":"5.15.190","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.149","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.103","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.44","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.16.4","status":"unaffected","lessThanOrEqual":"6.16.*","versionType":"semver"},{"version":"6.17","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bridge/br_multicast.c","net/bridge/br_private.h"]}],"references":["https://git.kernel.org/stable/c/34171b9e53bd1dc264f5556579f2b04f04435c73","https://git.kernel.org/stable/c/43e281fde5e76a866a4d10780c35023f16c0e432","https://git.kernel.org/stable/c/96476b043efb86a94f2badd260f7f99c97bd5893","https://git.kernel.org/stable/c/bdb19cd0de739870bb3494c815138b9dc30875c4","https://git.kernel.org/stable/c/5bf5fce8a0c2a70d063af778fdb5b27238174cdd","https://git.kernel.org/stable/c/d1547bf460baec718b3398365f8de33d25c5f36f","https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","https://cert-portal.siemens.com/productcert/html/ssa-082556.html","https://cert-portal.siemens.com/productcert/html/ssa-032379.html","https://cert-portal.siemens.com/productcert/html/ssa-019113.html","https://cert-portal.siemens.com/productcert/html/ssa-457936.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/39xxx/CVE-2025-39773.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-39773","state":"PUBLISHED","datePublished":"2025-09-11T16:56:26.820Z","dateUpdated":"2026-10-15T01:08:16.402Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.129Z"},"containers":{"cna":{"title":"net: bridge: fix soft lockup in br_multicast_query_expired()","descriptions":[{"lang":"en","value":"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   <IRQ>\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   </IRQ>\n\nThis issue can be reproduced with:\n  ip link add br0 type bridge\n  echo 1 > /sys/class/net/br0/bridge/multicast_querier\n  echo 0xffffffffffffffff >\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 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