# GHSA-f52g-6jhx-586p: Denial of Service in handlebars

> Attackers can cause a denial of service by forcing the handlebars parser into an endless loop with specially crafted templates.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Sep 2020

## What is GHSA-f52g-6jhx-586p?

GHSA-f52g-6jhx-586p is a denial of service vulnerability in handlebars, published on 3 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Affected versions of `handlebars` are vulnerable to Denial of Service. The package's parser may be forced into an endless loop while processing specially-crafted templates. This may allow attackers to exhaust system resources leading to Denial of Service.

## Recommendation

Upgrade to version 4.4.5 or later.

## Which versions are affected by GHSA-f52g-6jhx-586p?

2 open source packages ship an affected version, including handlebars.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `handlebars` | npm | From 4.0.0 | 4.4.5 |
| `handlebars` | npm | From 4.0.0 | 4.4.5 |

## How do I fix GHSA-f52g-6jhx-586p?

Upgrade handlebars to 4.4.5 or later.

## Is GHSA-f52g-6jhx-586p being exploited?

There is no known exploitation of GHSA-f52g-6jhx-586p in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-f52g-6jhx-586p and fix it if it is affected.

What it is: GHSA-f52g-6jhx-586p is a denial of service vulnerability in handlebars, published on 3 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-f52g-6jhx-586p in the wild and no public exploit code.

Affected packages and fixed versions:
- handlebars (npm): affected from 4.0.0; fixed in 4.4.5
- handlebars (npm): affected from 4.0.0; fixed in 4.4.5

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/GHSA-f52g-6jhx-586p/ (Markdown: https://insights.sbomify.com/GHSA-f52g-6jhx-586p/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-f52g-6jhx-586p

---
From sbomify Insights: https://insights.sbomify.com/GHSA-f52g-6jhx-586p/
Summaries are generated and may contain mistakes; the official description above is the record.