CVE-2025-39773: Linux kernel · net: bridge: fix soft lockup in br_multicast_query_expired()
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in d1547bf460baec718b3398365f8de33d25c5f36f : update Linux kernel when convenient.
Data as of 10 Nov 2026, 12:50 UTC
Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- Patch
- Available – fixed in d1547bf460baec718b3398365f8de33d25c5f36f, bdb19cd0de739870bb3494c815138b9dc30875c4, 96476b043efb86a94f2badd260f7f99c97bd5893 +3
Exploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 10 Nov 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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AI-suggested
This issue has been fixed in the Linux kernel. Users should update to a fixed kernel version that includes the patches identified by the commit hashes provided. No additional mitigation is required once the system is updated.
Description
A vulnerability in the Linux kernel bridge networking code can cause a soft lockup due to an integer overflow in the multicast query timer logic. Setting the multicast_query_interval to a large value causes a local time variable to overflow, triggering a timer loop and CPU soft lockup. This issue has been fixed by adding checks to enforce maximum query interval values.
References
- git.kernel.org/stable/c/34171b9e53bd1dc264f5556579f2b04f04435c73 (opens in a new tab)
- git.kernel.org/stable/c/43e281fde5e76a866a4d10780c35023f16c0e432 (opens in a new tab)
- git.kernel.org/stable/c/96476b043efb86a94f2badd260f7f99c97bd5893 (opens in a new tab)
- git.kernel.org/stable/c/bdb19cd0de739870bb3494c815138b9dc30875c4 (opens in a new tab)
- git.kernel.org/stable/c/5bf5fce8a0c2a70d063af778fdb5b27238174cdd (opens in a new tab)
- git.kernel.org/stable/c/d1547bf460baec718b3398365f8de33d25c5f36f (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00008.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-032379.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)