In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: reject...

CVE-2025-21826 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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.

Basic information

Type
unreviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
—
Source code
Not specified
Published (advisory)
2025-03-06 18:31:10 UTC
Updated
2026-05-12 15:30:51 UTC
NVD published
2025-03-06

EPSS Score

Score Percentile
0.03% 8.84%

CVSS Scores

Base score Version Severity Vector
5.5 3.1 —
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-8376-779w-5hcf ↗
CVE CVE-2025-21826 ↗

References

cvelogic Threat Intelligence