CWE-777 Regular Expression without Anchors

The product uses a regular expression to perform neutralization, but the regular expression omits one or more anchors that may allow malicious or malformed data to slip through.

• Availability, Confidentiality, Access Control: Bypass Protection Mechanism, Varies by Context — An unanchored regular expression in the context of an allowlist will possibly result in a protection mechanism failure. Malicious or malformed data may be included before or after any string matching the regular expression, allowing the data to enter trusted regions of the program. The type of malicious data that is allowed will depend on the context of the application and which anchors are omitted from the regular expression. The specific consequences will depend on what functionality the allowlist was protecting.

• [Implementation] Be sure to understand both what will be matched and what will not be matched by a regular expression. Anchoring the ends of the expression will allow the programmer to define an allowlist strictly limited to what is matched by the text in the regular expression. If you are using a package that only matches one line by default, ensure that you can match multi-line inputs if necessary.

• CVE-2022-30034: Chain: Web UI for a Python RPC framework does not use regex anchors to validate user login emails (CWE-777), potentially allowing bypass of OAuth (CWE-1390).