CVE-2025-21909
MediumIn the Linux kernel, the following vulnerability has been resolved: wifi: nl80211: reject cooked mode if it is set along with other flags It is possible to set both MONITOR_FLAG_COOK_FRAMES and MONITOR_FLAG_ACTIVE flags simultaneously on the same monitor interface from the userspace. This causes a sub-interface to be created with no IEEE80211_SDATA_IN_DRIVER bit set because the monitor interface is in the cooked state and it takes precedence over all other states. When the interface is then being deleted the kernel calls WARN_ONCE() from check_sdata_in_driver() because of missing that bit. Fix this by rejecting MONITOR_FLAG_COOK_FRAMES if it is set along with other flags. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
CVSS 3.1 score
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness type
CWE-362CVE-2025-21909 is a Race Condition vulnerability
What is Race Condition?
The product contains a code sequence that can run concurrently with other code, creating unexpected states. Learn more on MITRE CWE
Affected versions
Linux kernel versions
2.6.26
and later are affected. Fixed in
5.4.291,
5.10.235,
5.15.179,
6.1.131,
6.6.83,
6.12.19,
6.13.7,
6.14
and their respective stable series.
References
The following references provide additional information about CVE-2025-21909 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.
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PatchKernel patch commithttps://git.kernel.org/stable/c/236f41ca728f23210b31ed2d1d8a6df575a4b2d6
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PatchKernel patch commithttps://git.kernel.org/stable/c/351eb7ac53ff1cd94d893c0c4534ced2f36ae7d7
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PatchKernel patch commithttps://git.kernel.org/stable/c/49f27f29446a5bfe633dd2cc0cfebd48a1a5e77f
Frequently asked questions
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What is CVE-2025-21909?
CVE-2025-21909 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a Race Condition flaw (CWE-362) . It affects Linux kernel versions from 2.6.26 onward and has been patched in 5.4.291, 5.10.235, 5.15.179 and others. CVE-2025-21909 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2025-21909?
CVE-2025-21909 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2025-21909?
Yes — CVE-2025-21909 has been patched. Fixed versions include 5.4.291, 5.10.235, 5.15.179 and others. If you are running Linux kernel 2.6.26 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2025-21909 actively exploited?
No — CVE-2025-21909 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.
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What is Race Condition (CWE-362)?
The product contains a code sequence that can run concurrently with other code, creating unexpected states. View CWE-362 on MITRE CWE →