Data::Intern::Shared versions before 0.02 for Perl allow an out-of-bounds read via unvalidated slot, reverse and arena indices in si_idx_find. The at...
Description
Data::Intern::Shared versions before 0.02 for Perl allow an out-of-bounds read via unvalidated slot, reverse and arena indices in si_idx_find. The attach-time validator si_validate_header is thorough about the header and layout (magic, version, section offsets, total_size, count and arena_used) but
Remediation
Update EGOR Data::Intern::Shared to the latest version. Monitor for exploitation attempts and review access logs.
---METADATA---
VENDOR: Apereo
PRODUCT: CAS
AFFECTED_VERSIONS: 7.3.0 before 8.0.0-RC6
---END_METADATA---
Description Summary:
A cryptographic flaw in Apereo CAS allows unauthenticated attackers to decrypt webflow conversation states by exploiting AES-GCM initialization vector reuse.
Executive Summary:
Apereo CAS contains a critical cryptographic vulnerability that allows unauthenticated attackers to recover plaintext conversation state, leading to potential identity and session compromise.
Vulnerability Details
CVE-ID: CVE-2026-59099
Affected Software: Apereo CAS
Affected Versions: 7.3.0 before 8.0.0-RC6
Vulnerability: The application utilizes a fixed all-zero initialization vector (IV) with AES-GCM encryption, resulting in keystream reuse. This allows unauthenticated remote attackers to perform known-plaintext analysis on collected webflow execution tokens.
Business Impact
The ability to decrypt conversation states poses a severe threat to authentication security, potentially exposing sensitive session information or facilitating session hijacking. With a CVSS score of 9.1, this represents a critical risk to any enterprise relying on Apereo CAS for centralized authentication and identity management.
Remediation Plan
Immediate Action: Upgrade to version 8.0.0-RC6 or later to implement secure, unique initialization vector generation for all cryptographic operations.
Proactive Monitoring: Monitor authentication logs and webflow traffic for patterns indicative of automated token collection or high-frequency requests from single sources.
Compensating Controls: While no direct WAF rule can fix the underlying cryptographic flaw, rate-limiting login attempts can slow down the token collection process required for this attack.
Exploitation Status
Public Exploit Available: Unknown
Analyst Notes: As of Jul 2, 2026, there is no public information indicating active exploitation of this vulnerability. However, due to the nature of the flaw, the potential for exploitation is high.
Analyst Recommendation
This vulnerability undermines the fundamental security of the CAS identity provider. Organizations must treat this as a high-priority update to prevent the exposure of plaintext session data. Patching is the only effective way to resolve the underlying keystream reuse issue.