Description
The zend_string_extend function in Zend/zend_string.h in PHP through 7.1.5 does not prevent changes to string objects that result in a negative length, which allows remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact by leveraging a script's use of .= with a long string.
Remediation
References
Related Vulnerabilities
MediaWiki Resource Management Errors Vulnerability (CVE-2015-8002)
WordPress Plugin WP OAuth Server (OAuth Authentication) Security Bypass (3.1.4)
WordPress Plugin Simple Page Ordering Cross-Site Scripting (2.2.1)
WebLogic CVE-2021-2136 Vulnerability (CVE-2021-2136)
Apache HTTP Server Uncontrolled Resource Consumption Vulnerability (CVE-2009-1890)