v8n is a javascript validation library. Versions of v8n prior to 1.5.1 were found to have an inefficient regular expression complexity in the `lowercase()` and `uppercase()` regex which could lead to a denial of service attack. In testing of the `lowercase()` function a payload of 'a' + 'a'.repeat(i) + 'A' with 32 leading characters took 29443 ms to execute. The same issue happens with uppercase(). Users are advised to upgrade. There are no known workarounds for this issue.

v8n vulnerable to Inefficient Regular Expression Complexity