Cyber Resilience

CVE-2026-59099

Public PoC
Published
02 July 2026
Modified
14 July 2026
CVSS Score v4 9.3
Click a component to see what it means
Raw vectorCVSS: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 0.0055 45th percentile
Risk Priority 46 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

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 45th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

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)
CWE-323

Related Threats

CVEs Like This One

CVE-2026-81020Shared CWE-323
CVE-2025-61739Shared CWE-323
CVE-2026-81341Shared CWE-323
CVE-2025-46632Shared CWE-323
CVE-2026-5446Shared CWE-323
CVE-2026-55967Shared CWE-323
CVE-2024-21530Shared CWE-323
CVE-2024-36289Shared CWE-323
CVE-2026-3559Shared CWE-323
CVE-2025-59870Shared CWE-323

Affected Assets

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

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V6.8.3
  • V11.3.4

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover nonce reuse through static analysis, fuzzing, or known-answer tests.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles include correct use of cryptographic primitives such as unique nonces per key.

SC-13 Cryptographic Protection partial match

Selecting and implementing appropriate cryptographic algorithms and modes reduces nonce-reuse exposure.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
prevents

Secure SDLC practices directly prevent nonce/key reuse errors in cryptographic implementations.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.24 Use of cryptography partial match
prevents

Mandates proper cryptographic key and nonce management, directly preventing nonce/key-pair reuse.

A.8.28 Secure coding partial match
prevents

Secure-coding rules can require unique nonces, but the control is broader than this single weakness.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect nonce reuse, yet the control addresses many other issues beyond this CWE.

References