CVE-2026-74871: openssl_encrypt before 1.4.6 KDF Bypass via Sequential-XOR

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-17 · updated 2026-09-10
Weakness: CWE-916

Description

openssl_encrypt versions before 1.4.6 contain a key derivation flaw in sequential XOR composition mode where the last stage cancels out during key generation. When configured with a single KDF and no prior hashing stage, attackers can bypass memory-hard key derivation and perform offline password cracking at SHA-256 speed instead of the configured KDF cost.

Affected products

jahlives openssl_encrypt: before 1.4.6 — fixed in 1.4.6

How to fix

Upgrade to a fixed version: jahlives openssl_encrypt 1.4.6. Check the vendor advisory for mitigations.

References

https://github.com/jahlives/openssl_encrypt/security/advisories/GHSA-vxf9-vwp6-2w43
https://www.vulncheck.com/advisories/openssl-encrypt-before-kdf-bypass-via-sequential-xor

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