> CVE-2026-23986 [MEDIUM]

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PUBLISHED
2026-01-21 23:15
MODIFIED
2026-01-21 23:15
CVSS_SCORE V3
6.9
EPSS (Prob. Exploit)
0.27%
Top 81.8%
DATA SOURCES:
NVD đź”— 2026-01-22 CWE MITRE đź”— 2026-11-01 FIRST EPSS đź”— 2026-10-25 GITHUB đź”— 2026-10-28 OSV đź”— 2026-01-26

> DESCRIPTION

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.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Local (L)
Exploit nécessite un accès local au système
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
Unknown (P)
Interaction inconnue
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
High (H)
Modification totale des données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-61

> CWE DETAILED DESCRIPTIONS

CWE-61: UNIX Symbolic Link (Symlink) Following - The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

> GITHUB SECURITY ADVISORY

GHSA-4fqp-r85r-hxqh MODERATE

Copier safe template has arbitrary filesystem write access via directory symlinks when _preserve_symlinks: true

AFFECTED PACKAGES:
PIP / copier
< 9.11.2
Fixed in: 9.11.2

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Copier safe template has arbitrary filesystem write access via directory symlinks when _preserve_symlinks: true

AFFECTED PACKAGES:
Unknown / Unknown
79 versions affected
ALIASES:
GHSA-4fqp-r85r-hxqh

> HISTORIQUE DES MODIFICATIONS

Première apparition
21/01/2026 23:15
Source: NVD
📊 ENRICHISSEMENT 01/02/2026 06:44
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-61: UNIX Symbolic Link (Symlink) Following - The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of ...
Total des modifications: 1 Dernière mise à jour: 9 months ago

> REFERENCES

https://github.com/copier-org/copier/commit/b3a7b3772d17cf0e7a4481978188c9f536c8...
https://github.com/copier-org/copier/releases/tag/v9.11.2
https://github.com/copier-org/copier/security/advisories/GHSA-4fqp-r85r-hxqh
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