CVE-2026-74871
Received Received - Intake

Key Derivation Bypass in OpenSSL Encrypt

Publication date: 2026-08-17

Last updated on: 2026-08-17

Assigner: VulnCheck

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.

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Meta Information

Published
2026-08-17
Last Modified
2026-08-17
Generated
2026-08-17
AI Q&A
2026-08-17
EPSS Evaluated
N/A
NVD
CVE-2026-74871
EUVD
EUVD-2026-60090

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
openssl openssl_encrypt to 1.4.6 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-916 The product generates a hash for a password, but it uses a scheme that does not provide a sufficient level of computational effort that would make password cracking attacks infeasible or expensive.

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Executive Summary

This vulnerability affects openssl_encrypt versions before 1.4.6. It involves a flaw in sequential XOR composition mode where the last key derivation 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.

Detection Guidance

Check openssl_encrypt version with 'openssl_encrypt --version' or 'dpkg -l openssl_encrypt'. Inspect configuration files for single KDF usage without prior hashing stages. Look for files encrypted using --xor or --use-xor-composition flags.

Impact Analysis

If you use affected versions of openssl_encrypt with non-default configurations (single KDF, no prior hashing), attackers could crack passwords much faster than intended. This could lead to unauthorized access to encrypted data. Users should upgrade to version 1.4.6 or later and re-encrypt affected files.

Compliance Impact

This vulnerability could impact compliance by weakening data protection measures. GDPR requires appropriate technical measures for data security, and HIPAA mandates safeguards for protected health information. If passwords are cracked due to this flaw, organizations may fail to meet these requirements, risking legal penalties and data breaches.

Mitigation Strategies

Upgrade openssl_encrypt to version 1.4.6 or later. Re-encrypt any files created with vulnerable configurations. Disable sequential XOR composition mode if not required. Review and update key derivation configurations to use multiple KDF stages.

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