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.
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Fixes

Solution

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Workaround

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History

Mon, 17 Aug 2026 11:15:00 +0000

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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-17T12:47:06.168Z

Reserved: 2026-08-17T10:48:45.738Z

Link: CVE-2026-74900

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-17T11:16:45.050

Modified: 2026-08-17T11:16:45.050

Link: CVE-2026-74900

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses