Regular Expressions 101

Community Patterns

Catastrophic Backtrack

1

Regular Expression
PCRE (PHP <7.3)

/
(?:(?:(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)*(?:\.([a-z\x{00a1}-\x{ffff}]{2,})))(?::\d{2,5})?(?:\/[^\s]*)?
/
g

Description

This regexp matches urls, but causes catastrophic backtrack

Submitted by anonymous - 8 years ago