CVE-2025-54885 MEDIUM

CVE-2025-54885: Thinbus generates insufficient entropy: 252 bits vs minimum 256 bits

Vendor Simbo1905
Product thinbus-srp-npm
Weakness CWE-331
Published August 7, 2025
Last update August 7, 2025

CVSS base score

6.9/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U

What the vulnerability does

01Description

Thinbus Javascript Secure Remote Password is a browser SRP6a implementation for zero-knowledge password authentication. In versions 2.0.0 and below, a protocol compliance bug causes the client to generate a fixed 252 bits of entropy instead of the intended bit length of the safe prime (defaulted to 2048 bits). The client public value is being generated from a private value that is 4 bits below the specification. This reduces the protocol's designed security margin it is now practically exploitable. The servers full sized 2048 bit random number is used to create the shared session key and password proof. This is fixed in version 2.0.1.

Key dates

02Disclosure timeline

August 7, 2025 CVE published
August 7, 2025 Record updated