> CVE-2026-66066 [CRITICAL]

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PUBLISHED
2026-07-30 19:18
MODIFIED
2026-07-30 19:18
CVSS_SCORE V3
9.5
EPSS (Prob. Exploit)
27.86%
Top 1.9%
⚡ EPSS ÉLEVÉ (27.9%)
DATA SOURCES:
NVD 🔗 2026-07-30 RED HAT 🔗 2026-08-02 CWE MITRE 🔗 2026-11-01 FIRST EPSS 🔗 2026-10-25 GITHUB 🔗 2026-10-29 OSV 🔗 2026-08-06

> DESCRIPTION

Action Pack is a framework for handling and responding to web requests. In versions prior to 7.2.3.2, 8.0.5.1 and 8.1.3.1, Active Storage does not disable libvips operations marked unsafe for untrusted content, allowing a crafted upload to invoke such an operation. Consuming applications are affected when configured to use libvips and accept image uploads from untrusted users. An unauthenticated attacker may exploit this behavior to read arbitrary files accessible to the Rails process, including environment variables and application secrets. Exposure of credentials such as secret_key_base or external-service tokens may enable remote code execution or lateral movement. This issue has been fixed in versions 7.2.3.2, 8.0.5.1 and 8.1.3.1.

> 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:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
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
None (N)
Aucune interaction utilisateur nécessaire
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
High (H)
Divulgation totale 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
High
Divulgation totale d'informations
Intégrité
High
Modification totale des données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-1188

> CWE DETAILED DESCRIPTIONS

CWE-1188: Initialization of a Resource with an Insecure Default - The product initializes or sets a resource with a default that is intended to be changed by the product's installer, administrator, or maintainer, but the default is not secure.

> RED HAT SEVERITY ASSESSMENT

THREAT SEVERITY
Important

> GITHUB SECURITY ADVISORY

GHSA-xr9x-r78c-5hrm CRITICAL

Active Storage has possible arbitrary file read and remote code execution in Active Storage variant processing

AFFECTED PACKAGES:
RUBYGEMS / activestorage
>= 8.1.0.beta1, < 8.1.3.1
Fixed in: 8.1.3.1
RUBYGEMS / activestorage
>= 8.0.0.beta1, < 8.0.5.1
Fixed in: 8.0.5.1
RUBYGEMS / activestorage
< 7.2.3.2
Fixed in: 7.2.3.2

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Action Pack: Possible arbitrary file read and remote code execution in Active Storage variant processing

AFFECTED PACKAGES:
Unknown / Unknown
64 versions affected
ALIASES:
GHSA-xr9x-r78c-5hrm

> HISTORIQUE DES MODIFICATIONS

Première apparition
30/07/2026 19:18
Source: NVD
📊 ENRICHISSEMENT 02/08/2026 05:00
REDHAT
Champ modifié: Sévérité Red Hat
Ancienne valeur:
N/A
Nouvelle valeur:
{ "threat_severity": "Important", "severity_scale": null }
📊 ENRICHISSEMENT 02/08/2026 05:00
REDHAT
Champ modifié: Red Hat
Ancienne valeur:
Non
Nouvelle valeur:
Oui
📊 ENRICHISSEMENT 01/08/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-1188: Initialization of a Resource with an Insecure Default - The product initializes or sets a resource with a default that is intended to be changed by the product's installer, administrator, or...
Total des modifications: 3 Dernière mise à jour: 3 months ago

> REFERENCES

https://github.com/rails/rails/commit/1c01bb587206ee6eb0e1179c2cef96a6a47acb1e
https://github.com/rails/rails/commit/349e7a5d5b4b715af1e416db824f3c078a7d59e5
https://github.com/rails/rails/commit/d79b7f4aa17dec8ce4960fef05733c8c0c7ef49a
https://github.com/rails/rails/releases/tag/v7.2.3.2
https://github.com/rails/rails/releases/tag/v8.0.5.1
https://github.com/rails/rails/releases/tag/v8.1.3.1
https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm
https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2...
https://thehackernews.com/2026/07/critical-rails-flaw-could-let.html
http://www.openwall.com/lists/oss-security/2026/07/29/9
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