CVE-2026-62999 Details
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.
A vulnerability in the Copier library and CLI application, affecting versions 9.5.0 through 9.16.0, allows for a trust-prefix bypass via percent-encoded parent-directory segments in template URLs. This encoding can be exploited to match a trusted repository prefix before the URL is decoded, potentially leading to the execution of unsafe template features from an untrusted repository. The issue arises because the trust-prefix comparison does not account for encoded characters, allowing repositories outside the trusted prefix to be treated as safe after user interaction.
Users can update to Copier version 9.17.0, which addresses the vulnerability by decoding percent-encoded characters in URL paths before normalizing them for trust-prefix comparisons.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 31, 2026CISA-ADP
Assessed Jul 31, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/copier-org/copier/security/advisories/GHSA-34mv-rjq9-5mch | CISA-ADP | AdvisoryExploitRemedyVendor |
| https://github.com/copier-org/copier/commit/7408f0d6287a7bf452715fd9f25dc54eaba3c295 | [email protected] | Source CodeVendor |
| https://github.com/copier-org/copier/releases/tag/v9.17.0 | [email protected] | Release NotesVendor |
| https://github.com/copier-org/copier/security/advisories/GHSA-34mv-rjq9-5mch | [email protected] | AdvisoryExploitRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-180 | Incorrect Behavior Order: Validate Before Canonicalize | [email protected] |
| CWE-22 | Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Copier | >= 9.5.0, <= 9.16.0 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 31, 2026 | New CVE Received | [email protected] |
| Jul 31, 2026 | CVE Modified | CISA-ADP |