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CWE-185

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CWE-185

Incorrect Regular Expression

Class
Draft

Description

The product specifies a regular expression in a way that causes data to be improperly matched or compared.

When the regular expression is used in protection mechanisms such as filtering or validation, this may allow an attacker to bypass the intended restrictions on the incoming data.

Common Consequences

Scope

Other

Impact

Unexpected State, Varies by Context

Scope

Access Control

Impact

Bypass Protection Mechanism

Potential Mitigations

Implementation

Regular expressions can become error prone when defining a complex language even for those experienced in writing grammars. Determine if several smaller regular expressions simplify one large regular expression. Also, subject the regular expression to thorough testing techniques such as equivalence partitioning, boundary value analysis, and robustness. After testing and a reasonable confidence level is achieved, a regular expression may not be foolproof. If an exploit is allowed to slip through, then record the exploit and refactor the regular expression.

CVE-2002-2109

Regexp isn't "anchored" to the beginning or end, which allows spoofed values that have trusted values as substrings.

CVE-2005-1949

Regexp for IP address isn't anchored at the end, allowing appending of shell metacharacters.

CVE-2001-1072

Bypass access restrictions via multiple leading slash, which causes a regular expression to fail.

CVE-2000-0115

Local user DoS via invalid regular expressions.

CVE-2002-1527

chain: Malformed input generates a regular expression error that leads to information exposure.

CVE-2005-1061

Certain strings are later used in a regexp, leading to a resultant crash.

CVE-2005-2169

MFV. Regular expression intended to protect against directory traversal reduces ".../...//" to "../".

CVE-2005-0603

Malformed regexp syntax leads to information exposure in error message.

CVE-2005-1820

Code injection due to improper quoting of regular expression.

CVE-2005-3153

Null byte bypasses PHP regexp check.

+1 more examples

Applicable Platforms

Not Language-Specific

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