CVE-2025-45767: jose Library Weak Encryption Vulnerability

CVE-2025-45767 Overview

CVE-2025-45767 is a weak encryption vulnerability identified in jose version 6.0.10, a widely-used JavaScript library for JSON Object Signing and Encryption (JOSE) standards. The vulnerability relates to encryption implementation that reportedly does not meet recommended security standards, though this claim is disputed by third parties who note the assertion does not align with guidance from final security publications.

The jose library is commonly used in Node.js and browser-based applications for handling JSON Web Tokens (JWT), JSON Web Encryption (JWE), and JSON Web Signatures (JWS). A weakness in encryption implementation could potentially impact the confidentiality and integrity of data protected by the library.

Critical Impact

Applications using the affected version of jose may be vulnerable to cryptographic attacks that could compromise encrypted data confidentiality and integrity. The disputed nature of this CVE suggests organizations should evaluate their specific use cases.

Affected Products

• jose v6.0.10 (JavaScript/Node.js JOSE library)

Discovery Timeline

• August 1, 2025 - CVE-2025-45767 published to NVD
• August 21, 2025 - Last updated in NVD database

Technical Details for CVE-2025-45767

Vulnerability Analysis

This vulnerability is classified under CWE-327 (Use of a Broken or Risky Cryptographic Algorithm). The issue centers on the key length validation implemented within the jose library. According to the technical references, the library's check_key_length.ts module contains logic that may permit encryption operations with keys that do not conform to recommended security standards.

The vulnerability requires network access to exploit but has high attack complexity, meaning successful exploitation requires specific conditions to be met. If exploited, an attacker could potentially achieve limited compromise of data confidentiality and integrity, along with significant availability impact.

It is important to note that this CVE is disputed. Third-party analysis indicates that the characterization of the encryption as "not meeting recommended security standards" may not accurately reflect authoritative cryptographic guidance from final publications.

Root Cause

The root cause appears to be related to insufficient enforcement of cryptographic key length requirements in the jose library's encryption functions. The key length checking mechanism may allow cryptographic operations to proceed with key sizes that are considered inadequate by certain security recommendations.

The specific implementation concern can be found in the library's key length validation logic, which determines whether supplied keys meet minimum length requirements for the selected encryption algorithm.

Attack Vector

This is a network-based vulnerability with high attack complexity. An attacker would need to:

1. Identify applications using the vulnerable jose v6.0.10 library
2. Intercept or obtain encrypted data produced by the library
3. Exploit the weak encryption to potentially decrypt or tamper with the protected data

The lack of known exploits and the disputed status of this CVE suggest that practical exploitation may require specific circumstances or configurations.

For technical details on the vulnerability, refer to the GitHub Discussion Thread and the GitHub Gist Code Snippet documenting the reported issue.

Detection Methods for CVE-2025-45767

Indicators of Compromise

• Applications using jose version 6.0.10 in their dependency tree
• Encrypted payloads generated with potentially weak key configurations
• JWE tokens using encryption algorithms with insufficient key lengths

Detection Strategies

• Audit application dependencies using software composition analysis (SCA) tools to identify jose v6.0.10
• Review cryptographic configurations in applications using the jose library to verify appropriate key lengths are enforced
• Implement runtime monitoring for cryptographic operations that may use weak parameters

Monitoring Recommendations

• Monitor the jose GitHub repository for security advisories and updates
• Track the discussion thread for resolution status on this disputed CVE
• Review application logs for any cryptographic errors or warnings related to key length validation

How to Mitigate CVE-2025-45767

Immediate Actions Required

• Inventory all applications using the jose library and identify those running version 6.0.10
• Review the dispute commentary to assess the applicability of this vulnerability to your use case
• Ensure cryptographic operations use appropriately sized keys per NIST recommendations
• Consider updating to newer versions of the jose library if available

Patch Information

At the time of this writing, no specific patch information has been published in the CVE data. Given the disputed nature of this vulnerability, organizations should monitor the jose GitHub repository for official guidance from the library maintainer.

Review the key length check implementation to understand the current validation logic.

Workarounds

• Enforce minimum key length requirements at the application level before passing keys to the jose library
• Implement additional validation layers to ensure cryptographic keys meet organizational security policies
• Consider using application-level key length checks as a defense-in-depth measure regardless of library behavior

# Example: Check jose version in your Node.js project
npm list jose

# Update to latest version if available
npm update jose