Overview
CVE-2025-66017 identifies a significant vulnerability in the CGGMP24 ECDSA Threshold Signature Scheme (TSS) protocol, specifically affecting versions 0.6.3 and prior of cggmp21 and version 0.7.0-alpha.1 of cggmp24. The vulnerability stems from the misuse of pre-signatures, which could substantially weaken the overall security of the system. The release of cggmp24 version 0.7.0-alpha.2 addresses this issue with API changes that prevent insecure use of pre-signatures.
Technical Details
CGGMP24 is a state-of-the-art ECDSA TSS protocol designed for 1-round signing (requiring 3 preprocessing rounds), identifiable abort, and key refresh capabilities. The vulnerability lies in how pre-signatures were handled in earlier versions. Specifically, pre-signatures, intended as an optimization, could be leveraged in a way that compromises the intended security guarantees of the TSS scheme. While the advisory doesn’t explicitly state the exact method of exploitation (likely due to ongoing risk to unpatched systems), it highlights that inappropriate use of these pre-generated signatures significantly reduced security. Version 0.7.0-alpha.2 implements API changes that effectively eliminate this vulnerability by restricting how pre-signatures can be utilized, preventing the insecure patterns that led to the weakness.
CVSS Analysis
Currently, a CVSS score has not been assigned to CVE-2025-66017. The severity is also marked as N/A. However, given the nature of the vulnerability – a weakening of the cryptographic foundation of the TSS scheme – its potential impact is substantial. A CVSS score will likely be assigned once more detailed exploitation information is publicly available. It’s crucial to treat this vulnerability with high priority despite the missing score.
Possible Impact
The consequences of this vulnerability could be severe, particularly in applications relying on the security of ECDSA TSS. Potential impacts include:
- Compromised private keys: An attacker could potentially reconstruct or derive parts of the private key used in the TSS scheme.
- Unauthorized signing: Malicious actors might be able to generate valid signatures without the required threshold of key holders participating.
- Data breaches: If the signatures are used to protect sensitive data, a successful attack could lead to data breaches.
- Loss of trust: Compromised cryptographic systems erode trust in the overall application or service.
Mitigation or Patch Steps
The recommended mitigation is to upgrade to CGGMP24 version 0.7.0-alpha.2 or later. This version includes the necessary API changes to prevent the insecure use of pre-signatures. If you are using cggmp21, discontinue using versions 0.6.3 and prior and consider migrating to CGGMP24.
- Identify affected systems: Determine all systems using cggmp21 or CGGMP24.
- Upgrade libraries: Upgrade to CGGMP24 version 0.7.0-alpha.2 or later.
- Review Code: If you have custom implementations leveraging cggmp21 or CGGMP24, carefully review your code to ensure you are not using pre-signatures in a way that could be exploited.
- Testing: After applying the patch or upgrading, thoroughly test the system to ensure that the mitigation is effective and no regressions have been introduced.
