CWE-1333 454 CVEs MITRE definition ↗

CWE-1333: Inefficient Regular Expression Complexity

Overview

CWE-1333 (Inefficient Regular Expression Complexity) documents a weakness type used across vulnerability databases and security assessments. Use the sections below for definition, context, and mapped CVEs.

Security impact
Security impact: Depends on product and context; use CVE records, severity scores, and MITRE guidance to prioritize.

Description

The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.

Background details

Extended context from the CWE catalog (rendered from MITRE XHTML).

Some regular expression engines have a feature called "backtracking". If the token cannot match, the engine "backtracks" to a position that may result in a different token that can match.

Applicable platforms

Kind Name Class Prevalence OS / CPE
language Not Language-Specific Undetermined

Related CVEs in this database

These CVEs are mapped to this weakness in this database and kept for traceability and search.

CVE Published Summary
CVE-2026-49485 2026-07-17 HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.9 and 6.9.4.2, all implementations of FHIRPathEngine accept arbitrary FHIRPath exp…
CVE-2026-52746 2026-07-17 JSONata is a JSON query and transformation language. Prior to 2.2.0, malicious non-matching inputs to the $toMillis function can cause superlinear backtracking in the ISO-8601 validation regex, leadin…
CVE-2026-14741 2026-07-17 HTTP::Date versions before 6.08 for Perl allow CPU exhaustion via polynomial regex backtracking in parse_date. parse_date() matches the date string against a chain of alternative regexes, and str2tim…
CVE-2026-62237 2026-07-16 Grav before 2.0.4 contains a regular expression denial of service (ReDoS) vulnerability in the regex_replace filter and function, which are allowlisted in the Twig content sandbox. When Twig processin…
CVE-2026-45367 2026-07-16 HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.7, the FHIRPathEngine implementation passes user-controlled regular expressions fr…
CVE-2026-49477 2026-07-14 Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.8.4, the CSS selector parser in soupsieve contains a regular expression vulnerable to catastrophic backtracki…
CVE-2026-48801 2026-07-14 linkify-it is a links recognition library with full Unicode support. Prior to 5.0.1, LinkifyIt.prototype.match, the package's primary public API, has O(N²) algorithmic complexity for inputs containing…
CVE-2026-48125 2026-07-14 UAParser.js is a JavaScript library to detect browsers, operating systems, CPUs, and devices from user-agent data. From 2.0.1 until 2.0.10, a regular expression denial-of-service vulnerability exists …
CVE-2026-45305 2026-07-14 Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, Symfony\Component\Yaml\Parser::cleanup() used regular exp…
CVE-2026-45133 2026-07-14 Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.52, 6.4.40, 7.4.12, and 8.0.12, when the parser is exposed to attacker-controlled input, …
CVE-2026-45756 2026-07-14 Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 7.3.0-BETA1 until 7.4.12 and 8.0.12, the JsonPath component compiles attacker-controlled match() …
CVE-2026-6850 2026-07-13 Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to validate the length and content of message attachment field values, which allows an authenticated attacker to cause …
CVE-2026-57584 2026-07-10 Phalcon is a high-performance, full-stack PHP framework. Prior to 5.15.0, every Phalcon MVC application built with a default router registers a built-in route whose compiled PCRE pattern contains the …
CVE-2026-59220 2026-07-09 Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.2 before 0.10.0, the SKILL_MENTION_RE and strip_re regular expressions in backend/open_webui/utils/middle…
CVE-2026-55470 2026-07-08 HAPI FHIR is a complete implementation of the HL7 FHIR standard for healthcare interoperability in Java. Prior to 6.9.10, the fix for CVE-2026-45367 incompletely patched the DSTU2 module, leaving FHIR…
CVE-2026-15154 2026-07-08 A flaw was found in `guardrails-detectors`, a component of Red Hat OpenShift AI. This vulnerability, known as Regular Expression Denial of Service (ReDoS), allows a remote attacker to provide speciall…
CVE-2026-59928 2026-07-08 Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a Markdown document containing many repeated or distinct reference-link definitions causes quadratic work in src/mistune…
CVE-2026-59925 2026-07-08 Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, long sequences of well-formed double-asterisk or triple-asterisk emphasis pairs around a character cause quadratic work …
CVE-2026-59922 2026-07-08 Mistune is a Python Markdown parser with renderers and plugins. Prior to 3.3.0, a run of closed tilde, equals-sign, or caret marker pairs around a character causes quadratic work in src/mistune/plugin…
CVE-2026-14895 2026-07-07 String::Util versions before 1.36 for Perl are susceptible to a regular expression denial of service. The trim and rtrim functions stripped trailing whitespace with s/\s*$//u. Because \s* matches gre…

Content submission

Name
Anonymous External Contributor
Date
2021-01-17
Version
4.4

Content modifications

Date Name Version Importance Comment
2021-07-20 CWE Content Team 4.5 updated References
2021-10-28 CWE Content Team 4.6 updated Description
2022-04-28 CWE Content Team 4.7 updated Observed_Examples, Potential_Mitigations
2022-10-13 CWE Content Team 4.9 updated Observed_Examples, Relationships
2023-01-31 CWE Content Team 4.10 updated Demonstrative_Examples, Observed_Examples
2023-04-27 CWE Content Team 4.11 updated References, Relationships
2023-06-29 CWE Content Team 4.12 updated Mapping_Notes
2025-12-11 CWE Content Team 4.19 updated Detection_Factors, Weakness_Ordinalities
2026-04-30 CWE Content Team 4.20 updated Background_Details, Common_Consequences, Description, Diagram, Modes_of_Introduction
cvelogic Threat Intelligence