CVE-2026-65629 in jose
Summary
by MITRE • 10/26/2026
Use of Password Hash With Insufficient Computational Effort in the jose library allows an attacker who obtains a password-encrypted private-key export to recover the private key through an offline password-cracking attack.
When jose exports a password-encrypted private key with jose_jwk:to_der/2 (JOSE.JWK.to_der/2), the jose_jwk_der:to_binary/3 function in src/jwk/jose_jwk_der.erl serializes the key as a PKCS#8 EncryptedPrivateKeyInfo using the PBES2 scheme with hardcoded key-derivation parameters: PBKDF2-HMAC-SHA256 with an iteration count of 2048 and an 8-byte (64-bit) random salt. Neither value can be overridden by the caller.
Both values are far below current guidance (OWASP recommends on the order of 600,000 iterations for PBKDF2-HMAC-SHA256, and NIST recommends salts of at least 128 bits), so the key-stretching work factor is roughly 300 times lower than intended and the short salt reduces the cost of precomputation across keys. The symmetric encryption (AES-256-CBC with a 16-byte random IV) is not affected; the weakness is entirely in the derivation strength. An attacker who obtains one of these exported blobs (for example from a backup, configuration repository, object storage, or logs) can mount a cheap offline dictionary or brute-force attack against the export password, and success yields the full private key.
This issue affects jose: from 1.10.0 before 1.11.13.
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Analysis
by VulDB Data Team • 10/26/2026
The vulnerability identified in the JOSE library represents a critical weakness in cryptographic implementation regarding password-based key derivation functions. Specifically, when exporting a password-encrypted private key using the jose_jwk:to_der/2 function, the underlying serialization process utilizes PKCS#8 EncryptedPrivateKeyInfo with the PBES2 scheme. However, this implementation relies on hardcoded parameters for the key derivation step that are significantly weaker than modern security standards dictate. The library employs PBKDF2-HMAC-SHA256 but configures it with an iteration count of only 2048 and a salt length of just eight bytes or sixty-four bits. These values are static and cannot be overridden by the application developer, meaning every export generated by vulnerable versions suffers from this inherent deficiency regardless of how securely the password itself is chosen.
The operational impact of these suboptimal parameters is severe because they drastically reduce the computational effort required to recover the private key through offline attacks. Industry standards provide clear guidance on appropriate work factors for such operations. For instance, OWASP recommends an iteration count in the vicinity of 600,000 for PBKDF2-HMAC-SHA256 to ensure adequate resistance against brute-force attempts. Similarly, NIST guidelines suggest that salts should be at least one hundred twenty-eight bits long to prevent precomputation attacks and rainbow table usage. By utilizing an iteration count roughly three hundred times lower than recommended and a salt length half the size of the minimum standard, the effective security margin is eroded substantially. This makes it computationally feasible for attackers with moderate resources to perform dictionary or brute-force attacks against exported key files obtained from backups, configuration repositories, object storage systems, or application logs.
While the symmetric encryption component using AES-256-CBC with a sixteen-byte random initialization vector remains robust and is not directly compromised by this flaw, the weakness lies entirely in the derivation strength that protects the private key material. An attacker who gains access to one of these exported blobs can exploit the low work factor to recover the password efficiently. Once the password is recovered, the full private key is exposed, leading to a complete compromise of confidentiality and integrity for any systems relying on that specific key pair. This vulnerability affects versions of the jose library from 1.10.0 up until but not including version 1.11.13. To mitigate this risk, organizations must upgrade to patched versions where these parameters are aligned with current cryptographic best practices or implement alternative secure export mechanisms if upgrading is not immediately possible.