How severe is CVE-2025-21659?

CVE-2025-21659 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-2025-21659 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-21659?

CVE-2025-21659 primarily affects Linux Linux Kernel. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-21659?

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

Does CVE-2025-21659 have an EU (EUVD) identifier?

Yes. CVE-2025-21659 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2608.

When was CVE-2025-21659 published?

CVE-2025-21659 was published on 2025-01-21 and last updated on 2026-06-17.

CVE-2025-21659

CVE-2025-21659 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.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-2608
Affected product: Linux Linux Kernel
Published: 2025-01-21
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: netdev: prevent accessing NAPI instances from another namespace The NAPI IDs were not fully exposed to user space prior to the netlink API, so they were never namespaced. The netlink API must ensure that at the very least NAPI instance belongs to the same netns as the owner of the genl sock. napi_by_id() can become static now, but it needs to move because of dev_get_by_napi_id().

Frequently asked questions

What is CVE-2025-21659?: In the Linux kernel, the following vulnerability has been resolved: netdev: prevent accessing NAPI instances from another namespace The NAPI IDs were not fully exposed to user space prior to the netlink API, so they were never namespaced. The netlink API must ensure that at the very least NAPI instance belongs to the same netns as the owner of the genl sock. napi_by_id() can become static now, but it needs to move because of dev_get_by_napi_id().
How severe is CVE-2025-21659?: CVE-2025-21659 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-2025-21659 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-21659?: CVE-2025-21659 primarily affects Linux Linux Kernel. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-21659?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-21659 have an EU (EUVD) identifier?: Yes. CVE-2025-21659 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-2608.
When was CVE-2025-21659 published?: CVE-2025-21659 was published on 2025-01-21 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:*

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