CVE-2025-54885
Thinbus generates insufficient entropy: 252 bits vs minimum 256 bits
- State
- Published
- Severity
- 6.9 Medium
- Published
- Aug 7, 2025
- Updated
- Aug 7, 2025
- Reserved
- Jul 31, 2025
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | 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 | GitHub_M |
Weaknesses
- CWE-331 Insufficient Entropy
Affected Products
| Product | Versions |
|---|---|
thinbus-srp-npmsimbo1905 |
|
References
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