CVE-2026-74890 openssl_encrypt before 1.4.0 HMAC Authentication Bypass via Environment Variable

Critical 9.3 Published 17 Aug 2026 Updated 1 Oct 2026

Attackers with code execution can bypass HMAC integrity checks in openssl_encrypt by setting a specific environment variable, allowing unauthenticated ciphertext.

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

What is CVE-2026-74890?

CVE-2026-74890 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 CamelliaCipher that disables HMAC tag generation and verification when the PYTEST_CURRENT_TEST environment variable is set. Attackers with code execution can set this environment variable to produce unauthenticated ciphertext and bypass integrity protection on encrypted data.

Weakness: CWE-345

Which versions are affected by CVE-2026-74890?

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-2026-74890?

Upgrade openssl-encrypt to 1.4.0 or later.

Is CVE-2026-74890 being exploited?

There is no known exploitation of CVE-2026-74890 in the wild and no public exploit code.

All Jahlives Openssl Encrypt vulnerabilities

Sources

Also known as GHSA-8p4p-w6mq-4grq, GHSA-rvc2-5jxq-gpcj, PYSEC-2026-3766.