A vulnerability in the Joi validation library's isoDate string validation allows an attacker to cause a denial of service by sending a specially crafted string. The issue arises from a quadratic regular-expression backtracking problem that causes the validation to stall for a time proportional to the square of the input length. This can lead to significant application delays or stalls. Fixed versions are available in Joi 17.13.7 and 18.2.6.