CVE-2026-59099 Details
Description
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.
A cryptographic vulnerability has been identified in Apereo CAS versions 7.3.0 prior to 8.0.0-RC6. This vulnerability allows remote unauthenticated attackers to recover plaintext conversation state by exploiting the reuse of initialization vectors (IVs) in AES-GCM encryption. The issue arises because the same IV, set to all-zero, is used across the server's lifetime, leading to keystream reuse. Attackers can collect client-side webflow execution tokens from the login page and use known-plaintext analysis to decrypt webflow conversation states.
Users can upgrade to Apereo CAS version 8.0.0-RC6, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 6, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-323 | Reusing a Nonce, Key Pair in Encryption | [email protected] |
Affected Products
No affected product data is available for this CVE.
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 14, 2026 | CVE Modified | [email protected] |
| Jul 6, 2026 | CVE Modified | CISA-ADP |
| Jul 2, 2026 | New CVE Received | [email protected] |