# HSEC-2024-0001: Reflected XSS vulnerability in keter

> Reflected XSS in Keter allows attackers to inject scripts via Host header, potentially leading to session hijacking or data theft.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 14 Nov 2025

## What is HSEC-2024-0001?

HSEC-2024-0001 is a cross-site scripting vulnerability in keter, published on 14 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

# Reflected XSS vulnerability in keter

Keter is an app-server/reverse-proxy often used with webapps build on Yesod web-framework.

In the logic handling VHost dispatch, Keter was echoing back `Host` header value, unescaped,
as part of an HTML error page. This constitutes a reflected-XSS vulnerability. Although
not readily exploitable directly from a browser (where `Host` header can't generally assume
arbitrary values), it may become such in presence of further weaknesses in components
upstream of Keter in the http proxying chain. Therefore, AC:High in CVSS evaluation.

## Which versions are affected by HSEC-2024-0001?

1 open source package ship an affected version, including keter.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `keter` | Hackage | From 0.3.4 | 1.8.4 |

## How do I fix HSEC-2024-0001?

Upgrade keter to 1.8.4 or later.

## Is HSEC-2024-0001 being exploited?

There is no known exploitation of HSEC-2024-0001 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for HSEC-2024-0001 and fix it if it is affected.

What it is: HSEC-2024-0001 is a cross-site scripting vulnerability in keter, published on 14 Nov 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of HSEC-2024-0001 in the wild and no public exploit code.

Affected packages and fixed versions:
- keter (Hackage): affected from 0.3.4; fixed in 1.8.4

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/HSEC-2024-0001/ (Markdown: https://insights.sbomify.com/HSEC-2024-0001/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/HSEC-2024-0001

---
From sbomify Insights: https://insights.sbomify.com/HSEC-2024-0001/
Summaries are generated and may contain mistakes; the official description above is the record.