Weak key derivation via unsalted HKDF
Published Aug 17, 2026 · Updated Aug 17, 2026
Weak key derivation in jahlives OpenSSL Encrypt before 1.4.0 allows attackers to reduce derived-key strength via repeated identical inputs. The normalize_to_key_length_secure function in openssl_encrypt/modules/crypt_core.py and the parallel _normalize_bytes helper in parallel_kdf.py call HKDF with salt=None and a static info value, so the same input normalizes deterministically and all contexts share the same extract salt. Exploitation requires influence over or reliance on repeated key-normalization inputs; the flaw weakens cryptographic separation and multi-target resistance rather than directly exposing plaintext or executing code.
Summary
What happened
Weak key derivation in jahlives OpenSSL Encrypt before 1.4.0 allows attackers to reduce derived-key strength via repeated identical inputs. The normalize_to_key_length_secure function in openssl_encrypt/modules/crypt_core.py and the parallel _normalize_bytes helper in parallel_kdf.py call HKDF with salt=None and a static info value, so the same input normalizes deterministically and all contexts share the same extract salt. Exploitation requires influence over or reliance on repeated key-normalization inputs; the flaw weakens cryptographic separation and multi-target resistance rather than directly exposing plaintext or executing code.
The record
- CVE
- CVE-2026-74889
- Published
- Aug 17, 2026
- Updated
- Aug 17, 2026
- Vendor
- jahlives
- Product
- OpenSSL Encrypt
- Classifications
- CWE-326
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 17, 2026CVE publishedPublication date reported by the CVE source.
- Aug 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <1.4.0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
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Your stack
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