CVE-2026-57079 Path traversal in Net::BitTorrent
A malicious peer can write arbitrary files outside the download directory via path traversal in metadata, potentially leading to code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-57079?
CVE-2026-57079 is a medium-severity path traversal vulnerability in SANKO Net::BitTorrent, published on 30 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Net::BitTorrent versions before 2.1.0 for Perl write files outside the download directory via path traversal in peer-supplied metadata.
Net::BitTorrent validates file path components only on the .torrent-file ingest path. The peer and magnet metadata path (_on_metadata_received, reached from the BEP09 ut_metadata extension) passes attacker-supplied file names straight to Storage::add_file and Storage::_parse_file_tree, where Path::Tiny's child() does not collapse "..". A v2 file tree key, a v1 files[].path element, or a single-file name containing ".." segments therefore resolves outside the download directory.
Because the peer also controls the piece hashes and the served bytes, content verification passes, so a malicious magnet or peer writes attacker-chosen content to an attacker-chosen path on the downloading host.
Weakness: CWE-22
Which versions are affected by CVE-2026-57079?
How do I fix CVE-2026-57079?
No fix has been published for CVE-2026-57079 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-57079 being exploited?
There is no known exploitation of CVE-2026-57079 in the wild and no public exploit code.
Sources
Also known as GHSA-5gfq-2rx4-6vwv, GHSA-5wc6-r65f-62rr.