The php_url_parse_ex function in ext/standard/url.c in PHP before 5.5.38 allows remote attackers to cause a denial of service (buffer over-read) or possibly have unspecified other impact via vectors involving the smart_str data type.
Severity
CVSS 3.0
9.8 critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
4.9% chance of exploitation in the next 30 days; higher than 92% of CVEs (scores of 2026-10-31)