path-to-regexp

Important

• Fix CVE-2026-4926 (GHSA-j3q9-mxjg-w52f)
• Fix CVE-2026-4923 (GHSA-27v5-c462-wpq7)

Fixed

• Restricts wildcard backtracking when using more than 1 in a path (#421)

Changed

• Dedupes regex prefixes (#422)
  • This will result in shorter regular expressions for some cases using optional groups
• Rejects large optional route combinations (#424)
  • When using groups such as /users{/delete} it will restrict the number of generated combinations to < 256, equivalent to 8 top-level optional groups and unlikely to occur in a real world application, but avoids exploding the regex size for applications that accept user created routes

Changed

• Add custom error class (#398) 2a7f2a4
• Allow plain objects for TokenData (#391) 687a9bb
• Escape text should escape backslash (#390) a4a8552
• Improved error messages and stack size (#363) a6bdf40

Other

• Minifying the parser
  • PR (#401) 9df2448
  • PR (#395) 4a91505
  • Shaving some bytes d63f44b
  • Remove optional operator 973d15c

v8.2.0...v8.3.0

Fixed

• Allowing path-to-regexp to run on older browsers by targeting ES2015
  • Target ES2015 5969033
    • Also saved 0.22kb (10%!) by removing the private class field down level
  • Remove s flag from regexp 51dbd45

v8.1.0...v8.2.0

Added

• Adds pathToRegexp method back for generating a regex
• Adds stringify method for converting TokenData into a path string

v8.0.0...v8.1.0

Heads up! This is a fairly large change (again) and I need to apologize in advance. If I foresaw what this version would have ended up being I would not have released version 7. A longer blog post and explanation will be incoming this week, but the pivot has been due to work on Express.js v5 and this will the finalized syntax used in Express moving forward.

Edit: The post is out - https://blakeembrey.com/posts/2024-09-web-redos/

Added

• Adds key names to wildcards using *name syntax, aligns with : behavior but using an asterisk instead

Changed

• Removes group suffixes of ?, +, and * - only optional exists moving forward (use wildcards for +, {*foo} for *)
• Parameter names follow JS identifier rules and allow unicode characters

Added

• Parameter names can now be quoted, e.g. :"foo-bar"
• Match accepts an array of values, so the signature is now string | TokenData | Array<string | TokenData>

Removed

• Removes loose mode
• Removes regular expression overrides of parameters

https://github.com/pillarjs/path-to-regexp/compare/v7.1.0...v8.0.0

Added

• Support array inputs for match and pathToRegexp 3fdd88f

https://github.com/pillarjs/path-to-regexp/compare/v7.1.0...v7.2.0

Added

• Adds a strict option to detect potential ReDOS issues

Fixed

• Fixes separator to default to suffix + prefix when not specified
• Allows separator to be undefined in TokenData
  • This is only relevant if you are building TokenData manually, previously parse filled it in automatically

Comments

• I highly recommend enabling strict: true and I'm probably releasing a V8 with it enabled by default ASAP as a necessary security mitigation

https://github.com/pillarjs/path-to-regexp/compare/v7.0.0...v7.1.0

Hi all! There's a few major breaking changes in this release so read carefully.

Breaking changes:

• The function returned by compile only accepts strings as values (i.e. no numbers, use String(value) before compiling a path)
  • For repeated values, when encode !== false, it must be an array of strings
• Parameter names can contain all unicode identifier characters (defined as regex \p{XID_Continue}).
• Modifiers (?, *, +) must be used after a param explicitly wrapped in {}
  • No more implied prefix of / or .
• No support for arrays or regexes as inputs
• The wildcard (standalone *) has been added back and matches Express.js expected behavior
• Removed endsWith option
• Renamed strict: true to trailing: false
• Reserved ;, ,, !, and @ for future use-cases
• Removed tokensToRegexp, tokensToFunction and regexpToFunction in favor of simplifying exports
• Enable a "loose" mode by default, so / can be repeated multiple times in a matched path (i.e. /foo works like //foo, etc)
• encode and decode no longer receive the token as the second parameter
• Removed the ESM + CommonJS dual package in favor of only one CommonJS supported export
• Minimum JS support for ES2020 (previous ES2015)
• Encode defaults to encodeURIComponent and decode defaults to decodeURIComponent

Added:

• Adds encodePath to fix an issue around encode being used for both path and parameters (the path and parameter should be encoded slightly differently)
• Adds loose as an option to support arbitrarily matching the delimiter in paths, e.g. foo/bar and foo///bar should work the same
• Allow encode and decode to be set to false which skips all processing of the parameters input/output
• All remaining methods support TokenData (exported, returned by parse) as input
  • This should be useful if you are programmatically building paths to match or want to avoid parsing multiple times

Requests for feedback:

• Requiring {} is an obvious drawback but I'm seeking feedback on whether it helps make path behavior clearer
  • Related: Removing / and . as implicit prefixes
• Removing array and regex support is to reduce the overall package size for things many users don't need
• Unicode IDs are added to align more closely with browser URLPattern behavior, which uses JS identifiers

https://github.com/pillarjs/path-to-regexp/compare/v6.2.2...v7.0.0

Fixed

• Add backtrack protection to 6.x (#324) f1253b4

https://github.com/pillarjs/path-to-regexp/compare/v6.2.2...v6.3.0

No API changes. Documentation only release.

Changed

• Fix readme example c7ec332
• Update shield URL e828000

https://github.com/pillarjs/path-to-regexp/compare/v6.2.1...v6.2.2

Fixed

• Fix invalid matching of :name* parameter (#261) 762bc6b
• Compare delimiter string over regexp 86baef8

Added

• New example in documentation (#256) ae9e576
• Update demo link (#250) 77df638
• Update README encode example b39edd4

https://github.com/pillarjs/path-to-regexp/compare/v6.2.0...v6.2.1

Added

• Support named capturing groups for RegExps (#225)

Fixed

• Update strict flag documentation (#227)
• Ignore test files when bundling (#220)

Fixed

• Use /#? as default delimiter to avoid matching on query or fragment parameters
  • If you are matching non-paths (e.g. hostnames), you can adjust delimiter: '.'

This release reverts the prefix behavior added in v3 back to the behavior seen in v2. For the most part, path matching is backward compatible with v2 with these enhancements:

1. Support for nested non-capturing groups in regexp, e.g. /(abc(?=d))
2. Support for custom prefix and suffix groups using /{abc(.*)def}
3. Tokens in an unexpected position will throw an error
   • Paths like /test(foo previously worked treating ( as a literal character, now it expects ( to be closed and is treated as a group
   • You can escape the character for the previous behavior, e.g. /test\(foo

Changed

• Revert using any character as prefix, support prefixes option to configure this (starts as /. which acts like every version since 0.x again)
• Add support for {} to capture prefix/suffix explicitly, enables custom use-cases like /:attr1{-:attr2}?

No changes to path rules since 3.x, except support for nested RegEx parts in 4.x.

Changed

• Rename RegexpOptions interface to TokensToRegexpOptions
• Remove normalizePathname from library, document solution in README
• Encode using identity function as default, not encodeURIComponent

Removed

• Remove whitelist in favor of decodeURI (advanced behavior can happen outside path-to-regexp)

Fixed

• Remove usage of String.prototype.normalize to continue supporting IE

Added

• Add normalize whitelist of characters (defaults to /%.-)

Fixed

• Allow RegexpOptions in match(...) function

Fixed

• Normalize regexp spelling across 4.x

All path rules are backward compatible with 3.x, except for nested () and other RegEx special characters that were previously ignored.

Changed

• Export names have changed to support ES2015 modules in bundlers
• match does not default to decodeURIComponent

Added

• New normalizePathname utility for supporting unicode paths in libraries
• Support nested non-capturing groups within parameters
• Add tree-shaking (via ES2015 modules) for webpack and other bundlers

Fixed

• Add backtrack protection to 3.x release (#321) d31670a

https://github.com/pillarjs/path-to-regexp/compare/v3.2.0...v3.3.0

Added

• Add native match function to library

• Add sensitive option for tokensToFunction (#191)
• Add validate option to path functions (#178)

Fixed

• Add backtrack protection to 1.x release (#320) 925ac8e
• Fix re.exec('/test/route') result (#267) 32a14b0

https://github.com/pillarjs/path-to-regexp/compare/v1.8.0...v1.9.0

Added

• Backport TokensToFunctionOptions

Important

• Fix CVE-2026-4867 (GHSA-37ch-88jc-xwx2)

Full Changelog: https://github.com/pillarjs/path-to-regexp/compare/v0.1.12...v.0.1.13

Fixed

• Improved backtracking protection for 0.1.x, will break some previously valid paths (see previous advisory: https://github.com/pillarjs/path-to-regexp/security/advisories/GHSA-9wv6-86v2-598j)

https://github.com/pillarjs/path-to-regexp/compare/v0.1.11...v0.1.12

Changed

• Add error on bad input values 8f09549

https://github.com/pillarjs/path-to-regexp/compare/v0.1.10...v0.1.11