CVE-2026-62999 Path traversal in copier
Attackers can bypass trusted prefix restrictions using percent-encoded paths in template URLs, enabling execution of unsafe code from untrusted repositories.
- 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
- None listed
What is CVE-2026-62999?
CVE-2026-62999 is a high-severity path traversal vulnerability in copier-org copier, published on 31 Jul 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
Copier is a library and CLI app for rendering project templates. From 9.5.0 through 9.16.0, percent-encoded parent-directory segments or encoded path separators in a template URL can match a configured trusted repository prefix before an HTTP server or Git transport decodes the path, allowing unsafe template features from a repository outside the trusted prefix to run after user interaction. This issue is fixed in version 9.17.0.
Which versions are affected by CVE-2026-62999?
How do I fix CVE-2026-62999?
No fix has been published for CVE-2026-62999 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-2026-62999 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62999 exists.
Sources
Also known as GHSA-34mv-rjq9-5mch.