CVE-2026-74901 openssl_encrypt before 1.4.0 Authentication Bypass via AES-CTR Fallback

Critical 9.3 Published 17 Aug 2026 Updated 1 Oct 2026

Attackers can bypass integrity checks in openssl_encrypt by forcing a fallback to unauthenticated AES-CTR, enabling undetected ciphertext modification.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-74901?

CVE-2026-74901 is a critical vulnerability in Jahlives Openssl Encrypt, published on 17 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-347

Which versions are affected by CVE-2026-74901?

1 open source package ship an affected version, including openssl-encrypt. It affects 1 product.

Package	Affected	Fixed in
`openssl-encrypt` PyPI	All versions	`1.4.0`

Products include Jahlives Openssl Encrypt.

How do I fix CVE-2026-74901?

Upgrade openssl-encrypt to 1.4.0 or later.

Is CVE-2026-74901 being exploited?

There is no known exploitation of CVE-2026-74901 in the wild and no public exploit code.

All Jahlives Openssl Encrypt vulnerabilities

Sources

Also known as GHSA-jw8h-gwjw-g7rc, GHSA-w4j7-wfgw-r52w, PYSEC-2026-3773.