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CVE-2026-74900

CVE-2026-74900 · openssl_encrypt before 1.4.0 Weak Shared Secret via PQC Simulation Mode

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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.

CVSS 9.3 · Critical · EPSS 0.6% · Fix available

Published
Updated

Stack: python

Affected products and versions

  • openssl_encrypt

    Versions
    • ≥ 0, < 1.4.0: Affected (semver)
    • 1.4.0: Not affected (semver)

    Update to 1.4.0

  • openssl-encrypt PyPI

    Versions
    • 0.2.2
    • 0.2.3
    • 0.2.4
    • 0.2.5
    • 0.2.6
    • 0.3.0
    • 0.3.1
    • 0.3.2
    • 0.3.3
    • 0.4.0
    • 0.4.1
    • 0.4.2
    • 0.4.3
    • 0.4.4
    • 0.5.0
    • 0.5.1
    • 0.5.3
    • 0.6.0rc1
    • 0.7.0rc2
    • 0.7.1
    • 0.7.2
    • 0.8.0
    • 0.8.1
    • 0.8.2
    • 0.9.2
    • 1.0.0
    • 1.0.1
    • 1.0.2
    • 1.0.3
    • 1.1.0
    • 1.2.0
    • 1.2.1
    • 1.3.0
    • 1.3.1
    • 1.3.2
    • 1.3.3
    • 1.3.4
    • 1.3.5
    • 1.4.0b3
    • 1.4.0b4
    • 1.4.0b5
    • 1.4.0b6
    • 1.4.0b7
    • 1.4.0b8
    Affected ranges
    • ECOSYSTEM: < 1.4.0

    Update to 1.4.0

Original sources

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