CWE-624: Executable Regular Expression Error

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-624 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-624, Executable Regular Expression Error, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Address Executable Regular Expression Error during Implementation

MITRE associates mitigation with Implementation; documented detection approaches include Automated Static Analysis; recorded impacts include Execute Unauthorized Code or Commands. Use these source-defined anchors to turn CWE-624 into implementation, review, and verification checks for the affected component.

CWE-624: Executable Regular Expression Error — MITRE CWE

Triage CWE-624 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-624, Executable Regular Expression Error, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-624

Apply MITRE's full root-cause mapping guidance when using CWE-624, Executable Regular Expression Error. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-624 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-624, Executable Regular Expression Error. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-624: Executable Regular Expression Error?+

CWE-624: Executable Regular Expression Error is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product uses a regular expression that either (1) contains an executable component with user-controlled inputs, or (2) allows a user to enable execution by inserting pattern modifiers. Case (2) is possible in the PHP preg_replace() function, and possibly in other languages when a user-controlled input is inserted into a string that is later parsed as a regular expression.

What are the security consequences of Executable Regular Expression Error?+

If exploited, CWE-624 (Executable Regular Expression Error) it can compromise Confidentiality, Integrity and Availability, leading to outcomes such as Execute Unauthorized Code or Commands.

How do you prevent or mitigate Executable Regular Expression Error?+

Recommended mitigations for CWE-624 include: The regular expression feature in some languages allows inputs to be quoted or escaped before insertion, such as \Q and \E in Perl.

Which programming languages are affected by Executable Regular Expression Error?+

CWE-624 commonly affects PHP and Perl. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Executable Regular Expression Error?+

MITRE documents real CVEs mapped to CWE-624, including CVE-2006-2059, CVE-2005-3420, CVE-2006-2878 and CVE-2006-2908. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-624 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

CWE-624: Executable Regular Expression Error

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