{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-59099: Apereo CAS 7.3.0 < 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-59099","status":"final","version":"1","initial_release_date":"2026-07-02T19:42:51.897Z","current_release_date":"2026-07-02T19:42:51.897Z","revision_history":[{"date":"2026-07-02T19:42:51.897Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-59099 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-59099"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-59099"},{"category":"external","summary":"Maintainer Advisory","url":"https://apereo.github.io/2026/06/18/vuln/"},{"category":"external","summary":"Release Notes","url":"https://github.com/apereo/cas/releases/tag/v8.0.0-RC6"},{"category":"external","summary":"Researcher Disclosure","url":"https://github.com/geo-chen/oss/blob/main/cas.md"},{"category":"external","summary":"Fix Commit","url":"https://github.com/apereo/cas/commit/22c6f4adf738852782309b523b4e80371057f2d0"},{"category":"external","summary":"vulncheck.com","url":"https://www.vulncheck.com/advisories/apereo-cas-rc6-aes-gcm-nonce-reuse-information-disclosure"}]},"product_tree":{"branches":[{"category":"vendor","name":"apereo","branches":[{"category":"product_name","name":"cas","branches":[{"category":"product_version_range","name":">=7.3.0 <8.0.0-RC6","product":{"name":"apereo cas >=7.3.0 <8.0.0-RC6","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:apereo:cas:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-59099","title":"Apereo CAS 7.3.0 < 8.0.0-RC6 - AES-GCM Nonce Reuse Information Disclosure","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"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","baseScore":9.3,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"vendor_fix","details":"Update to a fixed version: 8.0.0-RC6.","product_ids":["CSAFPID-1"],"url":"https://github.com/apereo/cas/commit/22c6f4adf738852782309b523b4e80371057f2d0"}]}]}