# CVE-2025-57783: Improper header parsing may lead to request smuggling

> An unauthenticated attacker can exploit improper header parsing in Hiawatha web server to access restricted resources via request smuggling.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Jan 2026
- **Updated:** 26 Jan 2026
- **Also known as:** GHSA-mrpv-h52h-rxhw

## What is CVE-2025-57783?

CVE-2025-57783 is a medium-severity vulnerability in Hiawatha Web server, published on 26 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Improper header parsing may lead to request smuggling has been identified in Hiawatha webserver version 11.7 which allows an unauthenticated attacker to access restricted resources managed by Hiawatha webserver.

## Which versions are affected by CVE-2025-57783?

It affects 1 product.


Products: Hiawatha-Webserver Hiawatha.

## How do I fix CVE-2025-57783?

No fix has been published for CVE-2025-57783 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-57783 being exploited?

There is no known exploitation of CVE-2025-57783 in the wild and no public exploit code.

## Other vulnerabilities in Hiawatha Web server

- [CVE-2019-8358](https://insights.sbomify.com/CVE-2019-8358/): Path traversal in n/a (high 8.1)
- [CVE-2025-57784](https://insights.sbomify.com/CVE-2025-57784/): Tomahawk authentication timing attack due to usage of 'strcmp' (medium 4.0)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-57783 and fix it if it is affected.

What it is: CVE-2025-57783 is a medium-severity vulnerability in Hiawatha Web server, published on 26 Jan 2026. 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-2025-57783 in the wild and no public exploit code.

Affected product: Hiawatha Web server. 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-2025-57783/ (Markdown: https://insights.sbomify.com/CVE-2025-57783/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-57783
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-57783
- OSV: https://osv.dev/vulnerability/CVE-2025-57783

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-57783/
Summaries are generated and may contain mistakes; the official description above is the record.