# GHSA-f3vw-587g-r29g: Path Traversal in sapper

> Attackers can read sensitive server files via URL-encoded path traversal in Sapper applications, requiring an upgrade to mitigate.

- **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-f3vw-587g-r29g?

GHSA-f3vw-587g-r29g is a path traversal vulnerability in sapper, published on 3 Sep 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Versions of `sapper` prior to 0.27.11 are vulnerable to Path Traversal. It is possible to access sensitive files on the server through HTTP requests containing URL-encoded `../`.  

You may test a `sapper` application running in prod mode with `curl -vvv http://localhost:3000/client/750af05c3a69ddc6073a/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/%252e%252e/etc/passwd`.

## Recommendation

Upgrade to version 0.27.11 or later.

## Which versions are affected by GHSA-f3vw-587g-r29g?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `sapper` | npm | All versions | 0.27.11 |
| `sapper` | npm | All versions | 0.27.11 |

## How do I fix GHSA-f3vw-587g-r29g?

Upgrade sapper to 0.27.11 or later.

## Is GHSA-f3vw-587g-r29g being exploited?

There is no known exploitation of GHSA-f3vw-587g-r29g in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-f3vw-587g-r29g and fix it if it is affected.

What it is: GHSA-f3vw-587g-r29g is a path traversal vulnerability in sapper, 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-f3vw-587g-r29g in the wild and no public exploit code.

Affected packages and fixed versions:
- sapper (npm): affected all versions; fixed in 0.27.11
- sapper (npm): affected all versions; fixed in 0.27.11

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-f3vw-587g-r29g/ (Markdown: https://insights.sbomify.com/GHSA-f3vw-587g-r29g/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-f3vw-587g-r29g

---
From sbomify Insights: https://insights.sbomify.com/GHSA-f3vw-587g-r29g/
Summaries are generated and may contain mistakes; the official description above is the record.