How severe is CVE-2025-21909?

CVE-2025-21909 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-21909 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-21909?

CVE-2025-21909 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-21909?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-21909 have an EU (EUVD) identifier?

Yes. CVE-2025-21909 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-9412.

When was CVE-2025-21909 published?

CVE-2025-21909 was published on 2025-04-01 and last updated on 2026-06-17.

CVE-2025-21909

CVE-2025-21909 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-362.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-9412
Weakness: CWE-362
Affected product: Linux Linux Kernel
Published: 2025-04-01
Last modified: 2026-06-17

Description

In 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.

Frequently asked questions

What is CVE-2025-21909?: In 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.
How severe is CVE-2025-21909?: CVE-2025-21909 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-21909 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21909?: CVE-2025-21909 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-21909?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-21909 have an EU (EUVD) identifier?: Yes. CVE-2025-21909 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-9412.
When was CVE-2025-21909 published?: CVE-2025-21909 was published on 2025-04-01 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:*

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