CVE-2026-74901CWE-347

CVE-2026-74901

Critical · published August 17, 2026

CVSS v3.1

9.8

EPSS

Percentile

33.6

In the wild

Unconfirmed

What it is

openssl_encrypt versions before 1.4.0 contain an authentication bypass vulnerability in pqc.py where AES-GCM decryption failures trigger fallback to unauthenticated AES-CTR mode. Attackers can modify ciphertext in transit to bypass integrity verification and perform bit-flipping attacks without detection.

The record

Technical detail

CVSS v3.1: 9.8 · CRITICAL
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0: 9.3 · 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
EPSS: 0.00405 · 33.6th percentile
Weakness: CWE-347 · Improper Verification of Cryptographic Signature
Published: 2026-08-17T15:16Z

Affected products (1)

Product	Versions	Fixed in
jahlives/openssl_encrypt	< 1.4.0	1.4.0

References (2)

https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-w4j7-wfgw-r52w · [email protected]https://www.vulncheck.com/advisories/openssl-encrypt-before-authentication-bypass-via-aes-ctr-fallback · [email protected]

EPSS history

Timeline

17 AUG 11:04Z
openssl_encrypt before 1.4.0 Authentication Bypass via AES-CTR Fallback
cvelistv5