CVE-2026-74900

openssl_encrypt before 1.4.0 Weak Shared Secret via PQC Simulation Mode

Published Aug 17, 2026 CVSS 4.0 · 9.3 Critical EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
CPEs cpe:2.3:a:jahlives:openssl_encrypt:*:*:*:*:*:*:*:*
Type Values Removed Values Added
CPEs cpe:2.3:a:jahlives:openssl_encrypt:*:*:*:*:*:python:*:*
Type Values Removed Values Added
First Time appeared Jahlives
Jahlives openssl Encrypt
Vendors & Products Jahlives
Jahlives openssl Encrypt
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title openssl_encrypt before 1.4.0 Weak Shared Secret via PQC Simulation Mode
Weaknesses CWE-391
References
Metrics cvssV3_1

{'score': 9.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 9.3, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 1, 2026, 3:21 PM
Reserved
Aug 17, 2026, 10:48 AM
Status
Analyzed
Published
Aug 17, 2026, 11:16 AM
Modified
Sep 1, 2026, 3:24 PM