# CVE-2023-27371: Denial of service in n/a

> Remote attackers can cause a denial of service in applications using libmicrohttpd by sending malicious HTTP POST packets with null bytes in multipart boundaries.

- **Severity:** Medium 5.9 (`CVSS:3.1/AC:H/AV:N/A:H/C:N/I:N/PR:N/S:U/UI:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Feb 2023
- **Updated:** 14 Oct 2026
- **Also known as:** ALSA-2023:6566, ALSA-2023:7090, AZL-25347, CLSA-2025-1760026053, DEBIAN-CVE-2023-27371, DLA-3374-1, ECHO-f2fe-b06e-f61a, GHSA-x2hm-ghg4-c67m, OESA-2023-1171, RHSA-2023:6566, RHSA-2023:7090, RHSA-2024:0584, RHSA-2024:1109, RLSA-2023:6566, RLSA-2023:7090, SUSE-SU-2023:1686-1, SUSE-SU-2023:1686-2, SUSE-SU-2023:1944-1, UBUNTU-CVE-2023-27371, openSUSE-SU-2024:12739-1

## What is CVE-2023-27371?

CVE-2023-27371 is a medium-severity denial of service vulnerability in n/a, published on 28 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2023-27371?

It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `libmicrohttpd` | AlmaLinux:8 | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-devel` | AlmaLinux:8 | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-doc` | AlmaLinux:8 | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd` | AlmaLinux:9 | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-devel` | AlmaLinux:9 | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-doc` | AlmaLinux:9 | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd` | Red Hat:enterprise_linux:8::baseos | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-debuginfo` | Red Hat:enterprise_linux:8::crb | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-debugsource` | Red Hat:enterprise_linux:8::crb | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-devel` | Red Hat:enterprise_linux:8::crb | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd-doc` | Red Hat:enterprise_linux:8::crb | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd` | Red Hat:enterprise_linux:9::appstream | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-debuginfo` | Red Hat:enterprise_linux:9::appstream | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-debugsource` | Red Hat:enterprise_linux:9::appstream | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-debuginfo` | Red Hat:enterprise_linux:9::crb | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-debugsource` | Red Hat:enterprise_linux:9::crb | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-devel` | Red Hat:enterprise_linux:9::crb | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd-doc` | Red Hat:enterprise_linux:9::crb | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd` | Red Hat:rhel_eus:8.6::baseos | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd-debuginfo` | Red Hat:rhel_eus:8.6::baseos | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd-debugsource` | Red Hat:rhel_eus:8.6::baseos | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd-debuginfo` | Red Hat:rhel_eus:8.6::crb | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd-debugsource` | Red Hat:rhel_eus:8.6::crb | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd-devel` | Red Hat:rhel_eus:8.6::crb | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd-doc` | Red Hat:rhel_eus:8.6::crb | All versions | 1:0.9.59-2.el8_6.1 |
| `libmicrohttpd` | Red Hat:rhel_eus:8.8::baseos | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd-debuginfo` | Red Hat:rhel_eus:8.8::baseos | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd-debugsource` | Red Hat:rhel_eus:8.8::baseos | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd-debuginfo` | Red Hat:rhel_eus:8.8::crb | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd-debugsource` | Red Hat:rhel_eus:8.8::crb | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd-devel` | Red Hat:rhel_eus:8.8::crb | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd-doc` | Red Hat:rhel_eus:8.8::crb | All versions | 1:0.9.59-2.el8_8.1 |
| `libmicrohttpd` | Rocky Linux:8 | All versions | 1:0.9.59-3.el8 |
| `libmicrohttpd` | Rocky Linux:9 | All versions | 1:0.9.72-5.el9 |
| `libmicrohttpd` | SUSE:Linux Enterprise Micro 5.1 | All versions | 0.9.57-150000.3.3.1 |
| `libmicrohttpd` | SUSE:Linux Enterprise Micro 5.2 | All versions | 0.9.57-150000.3.3.1 |
| `libmicrohttpd` | SUSE:Linux Enterprise Micro 5.3 | All versions | 0.9.57-150000.3.3.1 |
| `libmicrohttpd` | SUSE:Linux Enterprise Micro 5.4 | All versions | 0.9.57-150000.3.3.1 |

Products: Gnu Libmicrohttpd.

## How do I fix CVE-2023-27371?

Upgrade to a fixed version.

## Is CVE-2023-27371 being exploited?

There is no known exploitation of CVE-2023-27371 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2025-59777](https://insights.sbomify.com/CVE-2025-59777/): Null dereference in GNU libbmicrohttpd (high 8.7)
- [CVE-2025-62689](https://insights.sbomify.com/CVE-2025-62689/): Null dereference in GNU libbmicrohttpd (high 8.7)
- [CVE-2013-7038](https://insights.sbomify.com/CVE-2013-7038/): Information disclosure in n/a (medium 6.4)
- [CVE-2013-7039](https://insights.sbomify.com/CVE-2013-7039/): Memory corruption in n/a (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-27371 and fix it if it is affected.

What it is: CVE-2023-27371 is a medium-severity denial of service vulnerability in n/a, published on 28 Feb 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-27371 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2023-27371/ (Markdown: https://insights.sbomify.com/CVE-2023-27371/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-27371
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-27371
- OSV: https://osv.dev/vulnerability/CVE-2023-27371

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-27371/
Summaries are generated and may contain mistakes; the official description above is the record.