# CVE-2026-34783: Ferret has a Path Traversal in IO::FS::WRITE allows arbitrary file write when scraping malicious websites

> A path traversal in Ferret allows malicious websites to write arbitrary files, potentially leading to remote code execution on the host.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H`)
- **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:** 6 Apr 2026
- **Updated:** 7 Apr 2026
- **Also known as:** GHSA-j6v5-g24h-vg4j, GO-2026-5452

## What is CVE-2026-34783?

CVE-2026-34783 is a high-severity path traversal vulnerability in MontFerret ferret, published on 6 Apr 2026. 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

Ferret is a declarative system for working with web data. Prior to 2.0.0-alpha.4, a path traversal vulnerability in Ferret's IO::FS::WRITE standard library function allows a malicious website to write arbitrary files to the filesystem of the machine running Ferret. When an operator scrapes a website that returns filenames containing ../ sequences, and uses those filenames to construct output paths (a standard scraping pattern), the attacker controls both the destination path and the file content. This can lead to remote code execution via cron jobs, SSH authorized_keys, shell profiles, or web shells. This vulnerability is fixed in 2.0.0-alpha.4.

Weakness: CWE-73 (External Control of File Name or Path), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-34783?

5 open source packages ship an affected version, including github.com/MontFerret/ferret/v2 and github.com/MontFerret/ferret. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/MontFerret/ferret/v2` | Go | All versions | 2.0.0-alpha.4 |
| `github.com/MontFerret/ferret/v2` | Go | All versions | 2.0.0-alpha.4 |
| `github.com/MontFerret/ferret/v2` | Go | All versions | 2.0.0-alpha.4 |
| `github.com/MontFerret/ferret` | Go | All versions to 0.18.1 | None |
| `github.com/MontFerret/ferret` | Go | All versions to 0.18.1 | None |

Products: Montferret Ferret.

## How do I fix CVE-2026-34783?

Upgrade github.com/MontFerret/ferret/v2 to 2.0.0-alpha.4 or later.

## Is CVE-2026-34783 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34783 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34783 and fix it if it is affected.

What it is: CVE-2026-34783 is a high-severity path traversal vulnerability in MontFerret ferret, published on 6 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34783 exists.

Affected packages and fixed versions:
- github.com/MontFerret/ferret/v2 (Go): affected all versions; fixed in 2.0.0-alpha.4
- github.com/MontFerret/ferret/v2 (Go): affected all versions; fixed in 2.0.0-alpha.4
- github.com/MontFerret/ferret/v2 (Go): affected all versions; fixed in 2.0.0-alpha.4
- github.com/MontFerret/ferret (Go): affected all versions up to 0.18.1; no fix listed
- github.com/MontFerret/ferret (Go): affected all versions up to 0.18.1; no fix listed

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-2026-34783/ (Markdown: https://insights.sbomify.com/CVE-2026-34783/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34783
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34783
- OSV: https://osv.dev/vulnerability/CVE-2026-34783

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34783/
Summaries are generated and may contain mistakes; the official description above is the record.