CVE-2026-74889: openssl_encrypt before 1.4.0 Weak Key Derivation via HKDF

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-17 · updated 2026-09-01
Weakness: CWE-326

Description

openssl_encrypt versions before 1.4.0 use HKDF with no salt and static info parameter in key normalization functions, reducing entropy extraction and determinism. Attackers can exploit predictable key derivation with identical inputs to weaken cryptographic security against multi-target attacks.

Affected products

jahlives openssl_encrypt: before 1.4.0 — fixed in 1.4.0

How to fix

Upgrade to a fixed version: jahlives openssl_encrypt 1.4.0. Check the vendor advisory for mitigations.

References

https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-j9mh-57cc-665x
https://www.vulncheck.com/advisories/openssl-encrypt-before-weak-key-derivation-via-hkdf

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