https://github.com/python-ldap/python-ldap/issues/424 Impact The LDAP schema parser of python-ldap 3.3.1 and earlier are vulnerable to a regular expression denial-of-service attack. The issue affects clients that use "ldap.schema" package to parse LDAP schema definitions from an untrusted source. Patches The upcoming release of python-ldap 3.4.0 will contain a workaround to prevent ReDoS attacks. The schema parser refuses schema definitions with an excessive amount of backslashes. Workarounds As a workaround, users can check input for excessive amount of backslashes in schemas. More than a dozen backslashes per line are atypical. References "CWE-1333" (https://cwe.mitre.org/data/definitions/1333.html) For more information If you have any questions or comments about this advisory: * Open an issue in "python-ldap" (https://github.com/python-ldap/python-ldap) tracker