Vulnerability · Published Aug 17, 2026 · Assigned by VulnCheck

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

Medium 5.5

In plain English

A medium-severity insufficient verification of data authenticity in openssl_encrypt from jahlives. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 12% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.5Medium

Exploit odds (30 days)0.2%top 88.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	openssl-encrypt	1.4.0	PYSEC-2026-3766

Affected products (as reported)

Vendor	Product	Versions
jahlives	openssl_encrypt	0 – before 1.4.0

Weakness: CWE-345 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

References

GitHub Security Advisory (GHSA-rvc2-5jxq-gpcj) vendor-advisory
VulnCheck Advisory: openssl_encrypt before 1.4.0 HMAC Authentication Bypass via Environment Variable third-party-advisory