CWE-625 Permissive Regular Expression

The product uses a regular expression that does not sufficiently restrict the set of allowed values.

• Access Control: Bypass Protection Mechanism — The regexp could accept substrings that match the pattern, which produces a partial comparison to the target. In some cases, this can allow dangerous substrings to bypass the intended protection.

• [Implementation] When applicable, ensure that the regular expression marks beginning and ending string patterns, such as "/^string$/" for Perl.

• Automated Static Analysis: Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

• CVE-2021-22204: Chain: regex in EXIF processor code does not correctly determine where a string ends (CWE-625), enabling eval injection (CWE-95), as exploited in the wild per CISA KEV. • CVE-2006-1895: ".*" regexp leads to static code injection • CVE-2002-2175: insertion of username into regexp results in partial comparison, causing wrong database entry to be updated when one username is a substring of another. • CVE-2006-4527: regexp intended to verify that all characters are legal, only checks that at least one is legal, enabling file inclusion. • CVE-2005-1949: Regexp for IP address isn't anchored at the end, allowing appending of shell metacharacters. • CVE-2002-2109: Regexp isn't "anchored" to the beginning or end, which allows spoofed values that have trusted values as substrings. • CVE-2006-6511: regexp in .htaccess file allows access of files whose names contain certain substrings • CVE-2006-6629: allow load of macro files whose names contain certain substrings.