CVE-2026-59099

Apereo CAS 7.3.0 before 8.0.0-RC6 contains a cryptographic vulnerability that allows remote unauthenticated attackers to recover plaintext conversation state by exploiting AES-GCM initialization vector reuse across the server lifetime. Attackers can collect multiple client-side webflow execution tokens from the unauthenticated login page and perform known-plaintext analysis to decrypt the webflow conversation state due to keystream reuse caused by a fixed all-zero IV paired with the same encryption key.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://apereo.github.io/2026/06/18/vuln/
https://github.com/apereo/cas/commit/22c6f4adf738852782309b523b4e80371057f2d0
https://github.com/apereo/cas/releases/tag/v8.0.0-RC6
https://github.com/geo-chen/oss/blob/main/cas.md
https://www.vulncheck.com/advisories/apereo-cas-rc6-aes-gcm-nonce-reuse-information-disclosure

Configurations

No configuration.

History

25 Oct 2026, 21:10

Type	Values Removed	Values Added
Summary		(es) Apereo CAS 7.3.0 anterior a 8.0.0-RC6 contiene una vulnerabilidad criptográfica que permite a atacantes remotos no autenticados recuperar el estado de conversación en texto plano explotando la reutilización del vector de inicialización AES-GCM a lo largo de la vida útil del servidor. Los atacantes pueden recolectar múltiples tokens de ejecución de webflow del lado del cliente desde la página de inicio de sesión no autenticada y realizar análisis de texto plano conocido para descifrar el estado de conversación del webflow debido a la reutilización del flujo de claves causada por un IV fijo de todo ceros emparejado con la misma clave de cifrado.

Information

Published : 2026-07-02 20:17

Updated : 2026-10-25 21:10

NVD link : CVE-2026-59099

Mitre link : CVE-2026-59099

CVE.ORG link : CVE-2026-59099

JSON object : View

Products Affected

No product.

CWE

CWE-323

Reusing a Nonce, Key Pair in Encryption

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