Cyber Resilience

CVE-2026-59099

CriticalPublic PoC

Published: 02 July 2026

Published
02 July 2026
Modified
02 July 2026
KEV Added
Patch
CVSS Score v4 9.3 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
EPSS Score 0.0036 27.6th percentile
Risk Priority 70 floored blend · peak EPSS

Summary

CVE-2026-59099 is a critical-severity Reusing a Nonce, Key Pair in Encryption (CWE-323) vulnerability in Github (inferred from references). Its CVSS base score is 9.3 (Critical).

Operationally, ranked at the 27.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability details

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…

more

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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

Github
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References