CVE-2025-37997: netfilter: ipset: fix region locking in hash types

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-29 · updated 2026-10-15
Weakness: CWE-667

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: fix region locking in hash types Region locking introduced in v5.6-rc4 contained three macros to handle the region locks: ahash_bucket_start(), ahash_bucket_end() which gave back the start and end hash bucket values belonging to a given region lock and ahash_region() which should give back the region lock belonging to a given hash bucket. The latter was incorrect which can lead to a race condition between the garbage collector and adding new elements when a hash type of set is defined with timeouts.

Affected products

Debian Linux: 11.0
Linux kernel: from 5.4.24 before 5.4.294; from 5.5.8 before 5.6; from 5.6.1 before 5.10.238; from 5.11 before 5.15.183; from 5.16 before 6.1.139; from 6.2 before 6.6.91 — fixed in 5.10.238, 5.15.183, 5.4.294, 5.6, 6.1.139, 6.12.29

How to fix

Upgrade to a fixed version: Linux kernel 5.10.238, 5.15.183, 5.4.294, 5.6. Check the vendor advisory for mitigations.

References

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