CVE-2025-39773net: bridge: fix soft lockup in br_multicast_query_expired()
Updated under an hour ago ()
Does this affect you?
It affects Linux and 6 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
In the Linux kernel, the following vulnerability has been resolved: net: bridge: fix soft lockup in br_multicast_query_expired() When set multicast_query_interval to a large value, the local variable 'time' in br_multicast_send_query() may overflow. If the time is smaller than jiffies, the timer will expire immediately, and then call mod_timer() again, which creates a loop and may trigger the following soft lockup issue. watchdog: BUG: soft lockup - CPU#1 stuck for 221s! [rb_consumer:66] CPU: 1 UID: 0 PID: 66 Comm: rb_consumer Not tainted 6.16.0+ #259 PREEMPT(none) Call Trace: <IRQ> __netdev_alloc_skb+0x2e/0x3a0 br_ip6_multicast_alloc_query+0x212/0x1b70 __br_multicast_send_query+0x376/0xac0 br_multicast_send_query+0x299/0x510 br_multicast_query_expired.constprop.0+0x16d/0x1b0 call_timer_fn+0x3b/0x2a0 __run_timers+0x619/0x950 run_timer_softirq+0x11c/0x220 handle_softirqs+0x18e/0x560 __irq_exit_rcu+0x158/0x1a0 sysvec_apic_timer_interrupt+0x76/0x90 </IRQ> This issue can be reproduced with: ip link add br0 type bridge echo 1 > /sys/class/net/br0/bridge/multicast_querier echo 0xffffffffffffffff > /sys/class/net/br0/bridge/multicast_query_interval ip link set dev br0 up The multicast_startup_query_interval can also cause this issue. Similar to the commit 99b40610956a ("net: bridge: mcast: add and enforce query interval minimum"), add check for the query interval maximum to fix this issue.
- CVSS
- 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from d902eee43f1951b358d7347d9165c6af21cf7b1b before 34171b9e53bd1dc264f5556579f2b04f04435c73; from d902eee43f1951b358d7347d9165c6af21cf7b1b before 43e281fde5e76a866a4d10780c35023f16c0e432; from d902eee43f1951b358d7347d9165c6af21cf7b1b before 96476b043efb86a94f2badd260f7f99c97bd5893; from d902eee43f1951b358d7347d9165c6af21cf7b1b before bdb19cd0de739870bb3494c815138b9dc30875c4; from d902eee43f1951b358d7347d9165c6af21cf7b1b before 5bf5fce8a0c2a70d063af778fdb5b27238174cdd; from d902eee43f1951b358d7347d9165c6af21cf7b1b before d1547bf460baec718b3398365f8de33d25c5f36f | CNA record |
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name) | before V5.0 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.5 | CISA ADP |
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name) | from V3.1.5 | CISA ADP |
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name) | from V3.1.5 | CISA ADP |
linux linux_kernel linux:linux_kernel | from 2.6.34 before 5.15.190; from 5.16 before 6.1.149; from 6.2 before 6.6.103; from 6.7 before 6.12.44; from 6.13 before 6.16.4; 6.17; 6.17 | NVD |
debian debian_linux debian:debian_linux | 11.0 | NVD |
References
- https://git.kernel.org/stable/c/34171b9e53bd1dc264f5556579f2b04f04435c73patch
- https://git.kernel.org/stable/c/43e281fde5e76a866a4d10780c35023f16c0e432patch
- https://git.kernel.org/stable/c/96476b043efb86a94f2badd260f7f99c97bd5893patch
- https://git.kernel.org/stable/c/bdb19cd0de739870bb3494c815138b9dc30875c4patch
- https://git.kernel.org/stable/c/5bf5fce8a0c2a70d063af778fdb5b27238174cddpatch
- https://git.kernel.org/stable/c/d1547bf460baec718b3398365f8de33d25c5f36fpatch
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.htmlthird-party-advisory
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.