# CVE-2026-5720: miniupnpd Integer Underflow SOAPAction Header Parsing

> Remote attackers can cause denial of service or information disclosure in miniupnpd via integer underflow in SOAPAction header parsing.

- **Severity:** High 7.1 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Apr 2026
- **Updated:** 14 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-5720, GHSA-q4xv-xmjx-4h94, UBUNTU-CVE-2026-5720, USN-8731-1

## What is CVE-2026-5720?

CVE-2026-5720 is a high-severity vulnerability in miniupnpd, published on 17 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

miniupnpd contains an integer underflow vulnerability in SOAPAction header parsing that allows remote attackers to cause a denial of service or information disclosure by sending a malformed SOAPAction header with a single quote. Attackers can trigger an out-of-bounds memory read by exploiting improper length validation in ParseHttpHeaders(), where the parsed length underflows to a large unsigned value when passed to memchr(), causing the process to scan memory far beyond the allocated HTTP request buffer.

Weakness: CWE-191 (Integer Underflow (Wrap or Wraparound)), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-5720?

It affects 1 product.


Products: Miniupnp Project Miniupnpd.

## How do I fix CVE-2026-5720?

Apply the vendor's patch.

## Is CVE-2026-5720 being exploited?

There is no known exploitation of CVE-2026-5720 in the wild and no public exploit code.

## Other vulnerabilities in miniupnpd

- [CVE-2013-0230](https://insights.sbomify.com/CVE-2013-0230/): Memory corruption in n/a (critical 10.0)
- [CVE-2017-8798](https://insights.sbomify.com/CVE-2017-8798/): Integer overflow in n/a (critical 9.8)
- [CVE-2017-1000494](https://insights.sbomify.com/CVE-2017-1000494/): Memory corruption in n/a (high 7.8)
- [CVE-2013-0229](https://insights.sbomify.com/CVE-2013-0229/): Denial of service in n/a (high 7.8)
- [CVE-2013-1461](https://insights.sbomify.com/CVE-2013-1461/): Null dereference in n/a (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-5720 and fix it if it is affected.

What it is: CVE-2026-5720 is a high-severity vulnerability in miniupnpd, published on 17 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-5720 in the wild and no public exploit code.

Affected product: miniupnpd. 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-2026-5720/ (Markdown: https://insights.sbomify.com/CVE-2026-5720/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-5720
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-5720
- OSV: https://osv.dev/vulnerability/CVE-2026-5720

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-5720/
Summaries are generated and may contain mistakes; the official description above is the record.