CVE-2025-37913: Linux kernel · net_sched: qfq: Fix double list add in class with netem as child qdisc
Source GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 13 Nov 2026, 19:33 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 20 May 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 13 Nov 2026.
What to do
AI-suggested
A patch has been applied to the Linux kernel to fix this issue by adding a check to prevent double list additions. Users should update their Linux kernel to a version that includes this fix once available. Since this is not a cloud service, manual patching is required. Patch status is not explicitly confirmed in the provided data; users should consult the official Linux kernel advisories for the fixed versions and apply updates accordingly.
Description
CVE-2025-37913 is a high-severity vulnerability in the Linux kernel's net_sched subsystem affecting the qfq queuing discipline when used with netem as a child qdisc. The flaw involves a double addition of the same classifier to a list due to reentrant enqueue callbacks, leading to memory corruption. This issue was fixed by adding a check to prevent duplicate list entries.
References
- nvd.nist.gov/vuln/detail/CVE-2025-37913 (opens in a new tab)
- git.kernel.org/stable/c/005a479540478a820c52de098e5e767e63e36f0a (opens in a new tab)
- git.kernel.org/stable/c/041f410aec2c1751ee22b8b73ba05d38c3a6a602 (opens in a new tab)
- git.kernel.org/stable/c/0aa23e0856b7cedb3c88d8e3d281c212c7e4fbeb (opens in a new tab)
- git.kernel.org/stable/c/0bf32d6fb1fcbf841bb9945570e0e2a70072c00f (opens in a new tab)
- git.kernel.org/stable/c/370218e8ce711684acc4cdd3cc3c6dd7956bc165 (opens in a new tab)
- git.kernel.org/stable/c/53bc0b55178bd59bdd4bcd16349505cabf54b1a2 (opens in a new tab)
- git.kernel.org/stable/c/a43783119e01849fbf2fe8855634e8989b240cb4 (opens in a new tab)
- git.kernel.org/stable/c/f139f37dcdf34b67f5bf92bc8e0f7f6b3ac63aa4 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/08/msg00010.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/10/msg00007.html (opens in a new tab)