Vulnerability · Published Aug 7, 2025 · Assigned by GitHub_M
CVE-2025-54885Thinbus generates insufficient entropy: 252 bits vs minimum 256 bits
Medium 6.9
In plain English
A medium-severity security flaw in thinbus-srp-npm from simbo1905. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | thinbus-srp | 2.0.1 | GHSA-8q6v-474h-whgg |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| simbo1905 | thinbus-srp-npm | < 2.0.1 |
Weakness: CWE-331 · 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