DavidOsipov PostQuantum-Feldman-VSS up to 0.7.6b0 feldman_vss.py secure_redundant_execution cryptographic primitive risky implementation

Summaryinfo

A vulnerability, which was classified as critical, has been found in DavidOsipov PostQuantum-Feldman-VSS up to 0.7.6b0. Impacted is the function secure_redundant_execution of the file feldman_vss.py. This manipulation causes cryptographic primitive risky implementation. This vulnerability is registered as CVE-2025-29779. It is feasible to perform the attack on the physical device. No exploit is available.

Detailsinfo

A vulnerability classified as critical was found in DavidOsipov PostQuantum-Feldman-VSS up to 0.7.6b0. Affected by this vulnerability is the function secure_redundant_execution of the file feldman_vss.py. The manipulation with an unknown input leads to a cryptographic primitive risky implementation vulnerability. The CWE definition for the vulnerability is CWE-1240. To fulfill the need for a cryptographic primitive, the product implements a cryptographic algorithm using a non-standard, unproven, or disallowed/non-compliant cryptographic implementation. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Post-Quantum Secure Feldman's Verifiable Secret Sharing provides a Python implementation of Feldman's Verifiable Secret Sharing (VSS) scheme. In versions 0.7.6b0 and prior, the `secure_redundant_execution` function in feldman_vss.py attempts to mitigate fault injection attacks by executing a function multiple times and comparing results. However, several critical weaknesses exist. Python's execution environment cannot guarantee true isolation between redundant executions, the constant-time comparison implementation in Python is subject to timing variations, the randomized execution order and timing provide insufficient protection against sophisticated fault attacks, and the error handling may leak timing information about partial execution results. These limitations make the protection ineffective against targeted fault injection attacks, especially from attackers with physical access to the hardware. A successful fault injection attack could allow an attacker to bypass the redundancy check mechanisms, extract secret polynomial coefficients during share generation or verification, force the acceptance of invalid shares during verification, and/or manipulate the commitment verification process to accept fraudulent commitments. This undermines the core security guarantees of the Verifiable Secret Sharing scheme. As of time of publication, no patched versions of Post-Quantum Secure Feldman's Verifiable Secret Sharing exist, but other mitigations are available. Long-term remediation requires reimplementing the security-critical functions in a lower-level language like Rust. Short-term mitigations include deploying the software in environments with physical security controls, increasing the redundancy count (from 5 to a higher number) by modifying the source code, adding external verification of cryptographic operations when possible, considering using hardware security modules (HSMs) for key operations.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2025-29779 since 03/11/2025. The exploitation appears to be difficult. Attacking locally is a requirement. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• DavidOsipov

Name

• PostQuantum-Feldman-VSS

Version

• 0.7.6b0

Website

• Product: https://github.com/DavidOsipov/PostQuantum-Feldman-VSS/

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CPE 2.2info

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