# 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.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/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:** No
- **Published:** 31 Jul 2026
- **Updated:** 31 Jul 2026
- **Also known as:** GHSA-34mv-rjq9-5mch

## 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.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-180 (Incorrect Behavior Order: Validate Before Canonicalize)

## 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.

## Is CVE-2026-62999 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62999 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62999 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62999 exists.

Affected product: copier-org copier. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-62999/ (Markdown: https://insights.sbomify.com/CVE-2026-62999/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62999
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62999
- OSV: https://osv.dev/vulnerability/CVE-2026-62999

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62999/
Summaries are generated and may contain mistakes; the official description above is the record.