CVE-2026-74900

Public PoC

Published

17 August 2026

Modified

17 August 2026

CVSS Score v4 9.3

Click a component to see what it means

Raw vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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 0.0034 27th percentile

Risk Priority 45 floored blend · peak EPSS

Summary

CVE-2026-74900 is a critical-severity Unchecked Error Condition (CWE-391) vulnerability. Its CVSS base score is 9.3 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 27th 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)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-60117

Vulnerability Data

openssl_encrypt versions before 1.4.0 contain a critical vulnerability in pqc.py where KEM decapsulation failures silently fall back to simulation mode, generating a deterministic shared secret from only 16 bytes of the private key and publicly available encapsulated key data. Attackers…

who obtain 16 bytes of the private key can compute the shared secret and decrypt all ciphertext, as the fallback triggers on any KEM failure without raising an error.

CWE(s): CWE-391

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1203 Exploitation for Client Execution Execution

Adversaries may exploit software vulnerabilities in client applications to execute code.

attack.mitre.org →

T1212 Exploitation for Credential Access Credential Access

Adversaries may exploit software vulnerabilities in an attempt to collect credentials.

attack.mitre.org →

Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-71325Shared CWE-391

CVE-2024-23326Shared CWE-391

CVE-2024-52316Shared CWE-391

CVE-2023-0572Shared CWE-391

Affected Assets

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can identify locations where error conditions are ignored or unhandled.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles require explicit handling of error conditions and exceptions during design and implementation.

SC-24 Fail in Known State partial match

Fail-to-known-state requirements limit blast radius when an unchecked error condition occurs.

SI-11 Error Handling partial match

Proper error handling ensures conditions produce actionable messages rather than allowing silent unexpected behavior.

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 full match

prevents

Secure SDLC practices include proper exception and error handling, eliminating the root cause of CWE-391.

PR.PS-04 mostly match

prevents

Requiring log generation makes ignored error conditions visible to monitoring, directly reducing the weakness impact.

DE.AE-02 partial match

prevents

Event analysis can surface consequences of unchecked errors but does not enforce error checking itself.

DE.CM-09 partial match

prevents

Runtime monitoring can detect anomalous behavior from ignored errors but does not prevent the coding flaw.

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.8.28 Secure coding mostly match

prevents

Secure coding standards directly prohibit ignoring exceptions and unchecked errors.

A.8.29 Security testing in development and acceptance mostly match

finds

Security testing can detect missing error handling before deployment.

A.8.25 Secure development life cycle partial match

prevents

Secure development life cycle requires systematic error handling, reducing unchecked conditions.

A.8.26 Application security requirements partial match

prevents

Application security requirements include explicit handling of error conditions.