> CVE-2026-39324 [CRITICAL]

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PUBLISHED
2026-04-07 18:16
MODIFIED
2026-04-07 18:16
CVSS_SCORE V3
9.3
EPSS (Prob. Exploit)
0.27%
Top 80.1%
DATA SOURCES:
NVD đź”— 2026-04-07 CWE MITRE đź”— 2026-11-01 FIRST EPSS đź”— 2026-11-08 OSV đź”— 2026-11-02

> DESCRIPTION

Rack::Session is a session management implementation for Rack. From 2.0.0 to before 2.1.2, Rack::Session::Cookie incorrectly handles decryption failures when configured with secrets:. If cookie decryption fails, the implementation falls back to a default decoder instead of rejecting the cookie. This allows an unauthenticated attacker to supply a crafted session cookie that is accepted as valid session data without knowledge of any configured secret. Because this mechanism is used to load session state, an attacker can manipulate session contents and potentially gain unauthorized access. This vulnerability is fixed in 2.1.2.

> 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:N/PR:N/UI:N/VC:H/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:N/AC:L/AT:N/PR:N/UI:N/VC:H/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
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-287 CWE-345 CWE-502 CWE-565

> CWE DETAILED DESCRIPTIONS

CWE-287: Improper Authentication - When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. | CWE-345: Insufficient Verification of Data Authenticity - The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data. | CWE-502: Deserialization of Untrusted Data - The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid. | CWE-565: Reliance on Cookies without Validation and Integrity Checking - The product relies on the existence or values of cookies when performing security-critical operations, but it does not properly ensure that the setting is valid for the associated user.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

Rack::Session::Cookie secrets: decrypt failure fallback enables secretless session forgery and Marshal deserialization

AFFECTED PACKAGES:
Unknown / Unknown
3 versions affected
ALIASES:
GHSA-33qg-7wpp-89cq

> HISTORIQUE DES MODIFICATIONS

Première apparition
07/04/2026 18:16
Source: NVD
đź“Š ENRICHISSEMENT 01/05/2026 06:01
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-287: Improper Authentication - When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. | CWE-345: Insufficient Verification of...
Total des modifications: 1 Dernière mise à jour: 6 months ago

> REFERENCES

https://github.com/rack/rack-session/security/advisories/GHSA-33qg-7wpp-89cq
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