CVE-2026-81689: openssl_encrypt before 1.4.9 Weak Pepper Key Derivation

Severity: high (CVSS 7.5 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: 2026-08-27 · updated 2026-09-03
Weakness: CWE-916

Description

openssl_encrypt versions before 1.4.9 derive the remote-pepper wrap key using unsalted HKDF-SHA256 or bare SHA-256 of the password, allowing identical keys across all users and files. Attackers with access to wrapped pepper blobs can precompute a single dictionary table and perform fleet-wide offline password guessing at hardware speed to recover user passwords.

Affected products

jahlives openssl_encrypt: before 1.4.9 — fixed in 1.4.9

How to fix

Upgrade to a fixed version: jahlives openssl_encrypt 1.4.9. Check the vendor advisory for mitigations.

References

https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-3v63-778v-3mvp
https://www.vulncheck.com/advisories/openssl-encrypt-before-1.4.9-weak-pepper-key-derivation

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