CVE-2026-62864

Ring's nested-params middleware has inefficient regular expression complexity

Published Oct 30, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
Description
Ring is a Clojure web applications library inspired by Python's WSGI and Ruby's Rack. Prior to 1.15.5, `wrap-nested-params` in the `ring.middleware.nested-params` namespace uses a backtracking regular expression to match parameter names from URL query strings and HTTP request bodies. An attacker can craft a parameter name that drives quadratic O(n^2) matching work, causing regular-expression denial of service in applications using the middleware. `Ring-Defaults` users are also exposed because nested-params is enabled by default. Applications omitting the middleware do not expose this parsing path. This issue is fixed in version 1.15.5.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Ring-clojure
Ring-clojure ring
Vendors & Products Ring-clojure
Ring-clojure ring
Type Values Removed Values Added
Description Ring is a Clojure web applications library inspired by Python's WSGI and Ruby's Rack. Prior to 1.15.5, `wrap-nested-params` in the `ring.middleware.nested-params` namespace uses a backtracking regular expression to match parameter names from URL query strings and HTTP request bodies. An attacker can craft a parameter name that drives quadratic O(n^2) matching work, causing regular-expression denial of service in applications using the middleware. `Ring-Defaults` users are also exposed because nested-params is enabled by default. Applications omitting the middleware do not expose this parsing path. This issue is fixed in version 1.15.5.
Title Ring's nested-params middleware has inefficient regular expression complexity
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Nov 2, 2026, 3:05 PM
Reserved
Jul 14, 2026, 9:10 PM
Status
Awaiting Analysis
Published
Oct 30, 2026, 9:17 PM
Modified
Nov 2, 2026, 7:34 PM
Severity
Important
Public date
Oct 30, 2026, 8:34 PM