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.
- 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
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.
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 | 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 include Montferret Ferret.
How do I fix CVE-2026-34783?
Upgrade github.com/MontFerret/ferret/v2 to 2.0.0-alpha.4 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-34783 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34783 exists.
Sources
Also known as GHSA-j6v5-g24h-vg4j, GO-2026-5452.