# CVE-2020-25691: Denial of service in darkhttpd

> Remote attackers can cause denial of service in darkhttpd by accessing files with large modification dates due to invalid error handling.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Apr 2022
- **Updated:** 4 Aug 2024
- **Also known as:** ALPINE-CVE-2020-25691, GHSA-4h33-v95w-8vh4

## What is CVE-2020-25691?

CVE-2020-25691 is a high-severity denial of service vulnerability in darkhttpd, published on 1 Apr 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A flaw was found in darkhttpd. Invalid error handling allows remote attackers to cause denial-of-service by accessing a file with a large modification date. The highest threat from this vulnerability is to system availability.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions)

## Which versions are affected by CVE-2020-25691?

It affects 1 product.


Products: Unix4lyfe Darkhttpd.

## How do I fix CVE-2020-25691?

Apply the vendor's patch.

## Is CVE-2020-25691 being exploited?

There is no known exploitation of CVE-2020-25691 in the wild and no public exploit code.

## Other vulnerabilities in darkhttpd

- [CVE-2024-23771](https://insights.sbomify.com/CVE-2024-23771/): Auth bypass in n/a (critical 9.8)
- [CVE-2024-23770](https://insights.sbomify.com/CVE-2024-23770/): Information disclosure in n/a (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-25691 and fix it if it is affected.

What it is: CVE-2020-25691 is a high-severity denial of service vulnerability in darkhttpd, published on 1 Apr 2022. 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-2020-25691 in the wild and no public exploit code.

Affected product: darkhttpd. 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-2020-25691/ (Markdown: https://insights.sbomify.com/CVE-2020-25691/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-25691
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-25691
- OSV: https://osv.dev/vulnerability/CVE-2020-25691

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-25691/
Summaries are generated and may contain mistakes; the official description above is the record.