{"id":"CVE-2026-59099","title":"Apereo CAS 7.3.0 < 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure","summary":"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. A…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","cvssSource":"cna","cwe":["CWE-323"],"vendor":"apereo","product":"cas","affected":["cas >= 7.3.0 < 8.0.0-RC6"],"ssvc":{"exploitation":"poc","automatable":"yes","technicalImpact":"total","timestamp":"2026-07-06T12:29:20.364889Z"},"exploitAvailable":true,"published":"2026-07-02","updated":"2026-11-08","sourceUpdated":"2026-11-08T14:07:20.381Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-59099","references":[{"url":"https://apereo.github.io/2026/06/18/vuln/","label":"Maintainer Advisory"},{"url":"https://github.com/apereo/cas/releases/tag/v8.0.0-RC6","label":"cas 8.0.0-RC6 Release Notes"},{"url":"https://github.com/geo-chen/oss/blob/main/cas.md","label":"Researcher Disclosure"},{"url":"https://github.com/apereo/cas/commit/22c6f4adf738852782309b523b4e80371057f2d0","label":"Fix Commit"},{"url":"https://www.vulncheck.com/advisories/apereo-cas-rc6-aes-gcm-nonce-reuse-information-disclosure"}],"tags":["cve.org","exploit-available"],"epss":0.00548,"epssPercentile":0.46177,"ingestedAt":"2026-11-08T14:51:22.285Z","slug":"CVE-2026-59099","body":"## Overview\n\nApereo 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.\n\n## Affected\n\n- `cas >= 7.3.0 < 8.0.0-RC6`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"abyssal","depthScore":62,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[]}