Copier
CVE-2026-23986
HIGH
GHSA-4fqp-r85r-hxqh
Severity by source
AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Lifecycle Timeline
4DescriptionGitHub Advisory
Copier is a library and CLI app for rendering project templates. Prior to version 9.11.2, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the --UNSAFE,--trust flag. As it turns out, a safe template can currently write to arbitrary directories outside the destination path by using directory a symlink along with _preserve_symlinks: true and a generated directory structure whose rendered path is inside the symlinked directory. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. Version 9.11.2 patches the issue.
AnalysisAI
Copier versions prior to 9.11.2 allow local attackers to write arbitrary files outside the intended project destination directory by exploiting symlink handling combined with the _preserve_symlinks feature in ostensibly safe templates. A malicious template author can craft a project template that bypasses security controls without requiring unsafe flags, enabling arbitrary file overwrites within the user's write permissions. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | User must run Copier to generate project from attacker-controlled template file locally. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 7.1 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker could exploit this vulnerability to compromise the affected system. |
| Remediation | A vendor patch is available — apply it immediately. Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 7 days: Identify all affected systems and apply vendor patches promptly. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
Share
External POC / Exploit Code
Leaving vuln.today