Inefficient Regular Expression Complexity
CWE-1333
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
We track 263 vulnerabilities of this type. 100% are rated high or critical, and the average CVSS score is 7.6.
How this weakness is prevented
- Architecture and Design: Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
- System Configuration: Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
- Implementation: Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
- Implementation: Limit the length of the input that the regular expression will process.
Latest Inefficient Regular Expression Complexity vulnerabilities
- 7.5 High severity
vllm: Inefficient Regular Expression Complexity
vLLM versions >= 0.6.3 and < 0.9.0 contain multiple regular expression denial of service (ReDoS) vulnerabilities. Several regex patterns — in vllm/lora/utils.py, the phi4mini tool parser, and the OpenAI-compatible serving chat endpoint — are susceptible to cat
- 7.5 High severity
js-toml: Uncontrolled Resource Consumption
js-toml is a TOML parser for JavaScript, fully compliant with the TOML 1.0.0 Spec. Versions up to and including 1.1.1 parse hexadecimal / octal / binary integer literals via a hand-written `parseBigInt` loop that multiplies a `BigInt` accumulator by the radix
- 7.5 High severity
liquidjs: Inefficient Regular Expression Complexity
LiquidJS is a Shopify/GitHub Pages compatible template engine written in pure JavaScript. In versions 10.25.7 and below, the built-in strip_html filter uses a regex containing four flawed lazy-quantified alternatives, leading to ReDoS via quadratic backtrackin
- 8.7 High severity
parse-server: Inefficient Regular Expression Complexity
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.77 and 9.9.1-alpha.1, an unauthenticated attacker who knows a publicly-known Parse Application ID can submit a single HTTP request who
- 7.5 High severity
axios: Uncontrolled Resource Consumption
Axios is a promise based HTTP client for the browser and Node.js. Axios versions before 0.32.0 on the 0.x line and before 1.16.0 on the 1.x line build a regular expression from the configured XSRF cookie name without escaping regex metacharacters. In standard
- 7.5 High severity
svelte: Inefficient Regular Expression Complexity
Svelte is a performance oriented web framework. From version 5.51.5 to before version 5.55.7, an internal regex in the Svelte runtime can take exponential time to test in <svelte:element this={tag}></svelte:element>. This issue has been patched in version 5.55
- 7.5 High severity
Spring Framework: Inefficient Regular Expression Complexity
Applications may be vulnerable to a Regular Expression Denial of Service (ReDoS) attack if an attacker is able to provide a pattern which is then directly or indirectly supplied to one of the following methods in AntPathMatcher: match(String pattern, String pa
- 9.8 Critical severity
yeswiki: Improper Control of Generation of Code
YesWiki is a wiki system written in PHP. Prior to version 4.6.6, an unsafe execution vulnerability exists in the Bazar form field calculator (CalcField.php) of YesWiki. The application attempts to sanitize user-defined mathematical formulas using a complex rec
- 7.5 High severity
Securly Chrome Extension: Improper Neutralization of Special Elements used in an Expression Language Statement
Version 3.0.7 of the Securly Chrome Extension downloads config.json over HTTP and compiles server-provided patterns as JavaScript regular expressions via new RegExp() without complexity validation. An on-path attacker can inject specific patterns to cause cata
- 7.5 High severity
pacote: Inefficient Regular Expression Complexity
Versions of the package pacote from 11.2.7 and before 21.5.1 are vulnerable to Denial of Service (DoS) via the addGitSha function. An attacker can exploit this vulnerability by supplying a specially crafted spec.rawSpec value that triggers the function’s regex
- 7.5 High severity
multiparty: Inefficient Regular Expression Complexity
[email protected] and lower versions are vulnerable to denial of service via regular expression backtracking in the Content-Disposition filename parameter parser. A crafted multipart upload with a long header value can cause regex matching to take seconds, bloc
- 7.5 High severity
mistune: Inefficient Regular Expression Complexity
In versions 3.0.0a1 through 3.2.0 of Mistune, there is a ReDoS (Regular Expression Denial of Service) vulnerability in `LINK_TITLE_RE` that allows an attacker who can supply Markdown for parsing to cause denial of service. The regular expression used for parsi
- 7.5 High severity
signalk-server: Uncontrolled Resource Consumption
Signal K Server is a server application that runs on a central hub in a boat. Versions prior to 2.25.0 are vulnerable to an unauthenticated Regular Expression Denial of Service (ReDoS) attack within the WebSocket subscription handling logic. By injecting unesc
- 7.5 High severity
addressable: Inefficient Regular Expression Complexity
Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 to before 2.9.0, within the URI template implementation in Addressable, two classes of URI template generate regular expressions vulnerab
- 8.7 High severity
gotenberg: Inefficient Regular Expression Complexity
Gotenberg is an API for converting document formats. In 8.29.1 and earlier, Gotenberg uses dlclark/regexp2 to compile user-supplied scope patterns without setting a proper timeout. Users with access to features using this logic can hang workers indefinitely.
- 7.5 High severity
content: Inefficient Regular Expression Complexity
@hapi/content provided HTTP Content-* headers parsing. All versions of @hapi/content through 6.0.0 are vulnerable to Regular Expression Denial of Service (ReDoS) via crafted HTTP header values. Three regular expressions used to parse Content-Type and Content-D
- 7.5 High severity
PraisonAI: Inefficient Regular Expression Complexity
PraisonAI is a multi-agent teams system. Prior to version 4.5.90, MCPToolIndex.search_tools() compiles a caller-supplied string directly as a Python regular expression with no validation, sanitization, or timeout. A crafted regex causes catastrophic backtracki
- 7.5 High severity
picomatch: Inefficient Regular Expression Complexity
Picomatch is a glob matcher written JavaScript. Versions prior to 4.0.4, 3.0.2, and 2.3.2 are vulnerable to Regular Expression Denial of Service (ReDoS) when processing crafted extglob patterns. Certain patterns using extglob quantifiers such as `+()` and `*()
- 7.5 High severity
path-to-regexp: Uncontrolled Resource Consumption
Impact: A bad regular expression is generated any time you have multiple sequential optional groups (curly brace syntax), such as `{a}{b}{c}:z`. The generated regex grows exponentially with the number of groups, causing denial of service. Patches: Fixed in ver
- 7.5 High severity
path-to-regexp: Inefficient Regular Expression Complexity
Impact: A bad regular expression is generated any time you have three or more parameters within a single segment, separated by something that is not a period (.). For example, /:a-:b-:c or /:a-:b-:c-:d. The backtrack protection added in [email protected] o
- 8.2 High severity
OpenClaw: Inefficient Regular Expression Complexity
OpenClaw versions prior to 2026.2.19 construct RegExp objects directly from unescaped Feishu mention metadata in the stripBotMention function, allowing regex injection and denial of service. Attackers can craft nested-quantifier patterns or metacharacters in m
- 7.5 High severity
multipart: Inefficient Regular Expression Complexity
multipart is a fast multipart/form-data parser for python. Prior to 1.2.2, 1.3.1 and 1.4.0-dev, the parse_options_header() function in multipart.py uses a regular expression with an ambiguous alternation, which can cause exponential backtracking (ReDoS) when p
- 7.5 High severity
elysia: Inefficient Regular Expression Complexity
Elysia is a Typescript framework for request validation, type inference, OpenAPI documentation and client-server communication. Prior to 1.4.26 , t.String({ format: 'url' }) is vulnerable to ReDoS. Repeating a partial url format (protocol and hostname) multipl
- 7.5 High severity
parse-server: Inefficient Regular Expression Complexity
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.5.0-alpha.14 and 8.6.11, a malicious client can subscribe to a LiveQuery with a crafted $regex pattern that causes catastrophic backtracking, blo
- 7.5 High severity
Red Hat Satellite 6.16 for RHEL 8: Inefficient Regular Expression Complexity
A flaw was found in REXML. A remote attacker could exploit inefficient regular expression (regex) parsing when processing hex numeric character references (&#x...;) in XML documents. This could lead to a Regular Expression Denial of Service (ReDoS), impacting
- 7.5 High severity
Kibana: Inefficient Regular Expression Complexity
Inefficient Regular Expression Complexity (CWE-1333) in the AI Inference Anonymization Engine in Kibana can lead Denial of Service via Regular Expression Exponential Blowup (CAPEC-492).
- 7.5 High severity
minimatch: Inefficient Regular Expression Complexity
minimatch is a minimal matching utility for converting glob expressions into JavaScript RegExp objects. Prior to version 10.2.3, 9.0.7, 8.0.6, 7.4.8, 6.2.2, 5.1.8, 4.2.5, and 3.1.4, nested `*()` extglobs produce regexps with nested unbounded quantifiers (e.g.
- 7.5 High severity
GitLab: Inefficient Regular Expression Complexity
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 9.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1 that could have allowed an unauthenticated user to cause regular expression denial of service by sending specially crafted
- 7.5 High severity
minimatch: Inefficient Regular Expression Complexity
minimatch is a minimal matching utility for converting glob expressions into JavaScript RegExp objects. Versions 10.2.0 and below are vulnerable to Regular Expression Denial of Service (ReDoS) when a glob pattern contains many consecutive * wildcards followed
- 7.5 High severity
markdown-it: Inefficient Regular Expression Complexity
Versions of the package markdown-it from 13.0.0 and before 14.1.1 are vulnerable to Regular Expression Denial of Service (ReDoS) due to the use of the regex /\*+$/ in the linkify function. An attacker can supply a long sequence of * characters followed by a no
- 9.2 Critical severity
brace-expansion: Inefficient Regular Expression Complexity
@isaacs/brace-expansion is a hybrid CJS/ESM TypeScript fork of brace-expansion. Prior to version 5.0.1, @isaacs/brace-expansion is vulnerable to a denial of service (DoS) issue caused by unbounded brace range expansion. When an attacker provides a pattern cont
- 7.5 High severity
apollo-server: Inefficient Regular Expression Complexity
Apollo Server is an open-source, spec-compliant GraphQL server that's compatible with any GraphQL client, including Apollo Client. In versions from 2.0.0 to 3.13.0, 4.2.0 to before 4.13.0, and 5.0.0 to before 5.4.0, the default configuration of startStandalone
- 7.5 High severity
jsdiff: Uncontrolled Resource Consumption
jsdiff is a JavaScript text differencing implementation. Prior to versions 8.0.3, 5.2.2, 4.0.4, and 3.5.1, attempting to parse a patch whose filename headers contain the line break characters `\r`, `\u2028`, or `\u2029` can cause the `parsePatch` method to ent
- 7.5 High severity
seroval: Inefficient Regular Expression Complexity
seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. In versions 0.2.0 through 1.4.0, overriding RegExp serialization with extremely large patterns can exhaust JavaScript runtime memory during deseriali
- 7.5 High severity
LangChain: Inefficient Regular Expression Complexity
LangChain versions up to and including 0.3.1 contain a regular expression denial-of-service (ReDoS) vulnerability in the MRKLOutputParser.parse() method (libs/langchain/langchain/agents/mrkl/output_parser.py). The parser applies a backtracking-prone regular ex
- 7.5 High severity
flagForge: Inefficient Regular Expression Complexity
Flag Forge is a Capture The Flag (CTF) platform. Versions 2.3.2 and below have a Regular Expression Denial of Service (ReDoS) vulnerability in the user profile API endpoint (/api/user/[username]). The application constructs a regular expression dynamically usi
- 7.5 High severity
MCP TypeScript SDK: Inefficient Regular Expression Complexity
Anthropic's MCP TypeScript SDK versions up to and including 1.25.1 contain a regular expression denial of service (ReDoS) vulnerability in the UriTemplate class when processing RFC 6570 exploded array patterns. The dynamically generated regular expression used
- 7.5 High severity
fedify: Inefficient Regular Expression Complexity
Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to versions 1.6.13, 1.7.14, 1.8.15, and 1.9.2, a Regular Expression Denial of Service (ReDoS) vulnerability exists in Fedify's document loader. The HTML parsing reg
- 7.5 High severity
valibot: Inefficient Regular Expression Complexity
Valibot helps validate data using a schema. In versions from 0.31.0 to 1.1.0, the EMOJI_REGEX used in the emoji action is vulnerable to a Regular Expression Denial of Service (ReDoS) attack. A short, maliciously crafted string (e.g., <100 characters) can cause
- 9.8 Critical severity
Zoom Workplace: Inefficient Regular Expression Complexity
Inefficient regular expression complexity in certain Zoom Workplace Clients before version 6.5.10 may allow an unauthenticated user to conduct an escalation of privilege via network access.