Is CVE-2026-74900 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-74900?

CVE-2026-74900 has a CVSS v3 severity of CRITICAL (9.8).

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CVE-2026-74900

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.