Description
The bcpowmod function in ext/bcmath/bcmath.c in PHP before 5.5.35, 5.6.x before 5.6.21, and 7.x before 7.0.6 modifies certain data structures without considering whether they are copies of the _zero_, _one_, or _two_ global variable, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted call.
Remediation
References
Related Vulnerabilities
Apache Tomcat Improper Certificate Validation Vulnerability (CVE-2018-8034)
Joomla Insufficient Verification of Data Authenticity Vulnerability (CVE-2020-15699)
Apache Tomcat Permissions, Privileges, and Access Controls Vulnerability (CVE-2007-5342)
Atlassian Jira Incorrect Default Permissions Vulnerability (CVE-2019-14995)