{"id":"CVE-2026-59099","aliases":["EUVD-2026-41430","GHSA-phqw-pwxm-86gq"],"status":"published","title":"Apereo CAS 7.3.0 \u003c 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure","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.","severity":{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00548,"percentile":0.46373,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-323"],"published":"2026-07-02T19:42:51Z","modified":"2026-11-08T14:07:20Z","products":[{"vendor":"apereo","product":"cas"}],"references":[{"url":"https://apereo.github.io/2026/06/18/vuln/","tags":["vendor-advisory","advisory"]},{"url":"https://github.com/apereo/cas/releases/tag/v8.0.0-RC6","tags":["release-notes","advisory"]},{"url":"https://github.com/geo-chen/oss/blob/main/cas.md","tags":["technical-description","exploit","evidence"]},{"url":"https://github.com/apereo/cas/commit/22c6f4adf738852782309b523b4e80371057f2d0","tags":["patch","fix"]},{"url":"https://www.vulncheck.com/advisories/apereo-cas-rc6-aes-gcm-nonce-reuse-information-disclosure","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59099","tags":["advisory"]},{"url":"https://apereo.github.io/2026/06/18/vuln"},{"url":"https://github.com/advisories/GHSA-phqw-pwxm-86gq"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59099.json","tags":["advisory"]},{"url":"https://github.com/apereo/cas","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-59099","title":"Apereo CAS 7.3.0 \u003c 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure","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.","status":"published","published":"2026-07-02T19:42:51.897Z","modified":"2026-11-08T14:07:20.381Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical","assessor":"cna"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"cna"}],"cwes":["CWE-323"],"updated_at":"2026-11-08T15:43:33.322657Z"}],"euvd":[{"id":"EUVD-2026-41430","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.","status":"published","published":"2026-07-02T19:42:51Z","modified":"2026-11-08T14:07:20Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical"}],"updated_at":"2026-11-08T15:13:07.123106Z"}],"ghsa":[{"id":"GHSA-phqw-pwxm-86gq","title":"Apereo CAS 7.3.0 before 8.0.0-RC6 contains a cryptographic vulnerability that allows remote...","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.","status":"published","published":"2026-07-02T21:32:14Z","modified":"2026-07-02T21:32:15Z","cvss":[{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"},{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/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","level":"critical"}],"cwes":["CWE-323"],"updated_at":"2026-11-02T15:09:12.451783Z"}],"nvd":[{"id":"CVE-2026-59099","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.","status":"published","published":"2026-07-02T20:17:08.24Z","modified":"2026-10-25T21:10:00.77Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/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","level":"critical","assessor":"secondary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"secondary"}],"cwes":["CWE-323"],"updated_at":"2026-11-02T14:12:27.541515Z"}],"osv":[{"id":"CVE-2026-59099","title":"Apereo CAS 7.3.0 \u003c 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure","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.","status":"published","published":"2026-07-02T19:42:51.897Z","modified":"2026-11-09T02:30:20.994421358Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical"}],"cwes":["CWE-323"],"updated_at":"2026-11-09T03:16:48.35602Z"}]}}