by Kastro
Paper/Archive/CVE-2026-74900

CVE-2026-74900

jahlives openssl_encrypt — openssl_encrypt before 1.4.0 Weak Shared Secret via PQC Simulation Mode

EPSS 0.6%CVSS 9.8
critical.is priorityof 100
39
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 46.5.465 × 209.3No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
openssl_encrypt< 1.4.01.4.0CNA

Scores by source

VulnCheck (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)9.3CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

advisorygithub.com/jahlives/openssl_encrypt/security/advisories/GHSA-p3gq-pcg9-qvfvwriteupvulncheck.com/advisories/openssl-encrypt-before-weak-shared-secret-via-pqc-simulation-mode