Medium (5.3) in express-mock-middleware project express-mock-middleware. EPSS 1.3% chance of exploitation in the next 30 days.
express-mock-middleware through 0.0.6 is vulnerable to Prototype Pollution. Exported functions by the package can be tricked into adding or modifying properties of the `Object.prototype`. Exploitation of this vulnerability requires creation of a new directory where an attack code can be placed which will then be exported by `express-mock-middleware`. As such, this is considered to be a low risk.
Severity
CVSS 3.1
5.3 medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS
1.3% chance of exploitation in the next 30 days; higher than 69% of CVEs (scores of 2026-10-31)