Path Traversal in Montferret Ferret
CVE-2026-34783
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.
Vulnerability class: Path Traversal (Directory Traversal)
EPSS: 0.005 (40.8th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H.
Affected products
- Montferret Ferret — versions 2.0.0, < 2.0.0-alpha.4
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-34783?
- CVE-2026-34783 is a high-severity vulnerability in Montferret Ferret, classified under Path Traversal. CVSS score: 8.1/10. Published 2026-04-06.
- How severe is CVE-2026-34783?
- High severity. CVSS v3 base score is 8.1 out of 10.