CVE-2025-21826

CVE-2025-21826 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

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: reject mismatching sum of field_len with set key length The field length description provides the length of each separated key field in the concatenation, each field gets rounded up to 32-bits to calculate the pipapo rule width from pipapo_init(). The set key length provides the total size of the key aligned to 32-bits. Register-based arithmetics still allows for combining mismatching set key length and field length description, eg. set key length 10 and field description [ 5, 4 ] leading to pipapo width of 12.

Frequently asked questions

What is CVE-2025-21826?
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: reject mismatching sum of field_len with set key length The field length description provides the length of each separated key field in the concatenation, each field gets rounded up to 32-bits to calculate the pipapo rule width from pipapo_init(). The set key length provides the total size of the key aligned to 32-bits. Register-based arithmetics still allows for combining mismatching set key length and field length description, eg. set key length 10 and field description [ 5, 4 ] leading to pipapo width of 12.
How severe is CVE-2025-21826?
CVE-2025-21826 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-2025-21826 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-2025-21826?
CVE-2025-21826 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-21826?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-21826 have an EU (EUVD) identifier?
Yes. CVE-2025-21826 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-6219.
When was CVE-2025-21826 published?
CVE-2025-21826 was published on 2025-03-06 and last updated on 2026-06-17.

References

Affected products (1)

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