Description
mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.7.1, web_url_read in src/index.ts passes a caller-supplied URL to readUrlContent() in src/url-reader.ts, where checkContentLength() treats a missing Content-Length header as an inconclusive preflight and the normal and error paths then consume the complete body with response.text(). A server that omits Content-Length can therefore bypass URL_READ_MAX_CONTENT_LENGTH_BYTES and force unbounded memory use. The resulting string is also processed by NodeHtmlMarkdown.translate(), increasing CPU consumption and allowing an unauthenticated HTTP client to cause denial of service. This issue is fixed in version 1.7.1.
Published: 2026-09-15
Score: 7.5 High
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service via unbounded memory/CPU usage
Action: Immediate Patch
AI Analysis

Impact

The vulnerability allows an unauthenticated attacker to send a request to the web_url_read endpoint with a URL that points to a server lacking a Content-Length header. The server then reads the entire response body into memory and processes it, bypassing the configured size limit and creating a scenario where memory or CPU resources can be exhausted. This results in denial of service. The weakness is represented by CWE-400.

Affected Systems

The issue affects the mcp-searxng Model Context Protocol server developed by ihor-sokoliuk. All versions prior to 1.7.1 are vulnerable. The vulnerable code resides in src/index.ts and src/url-reader.ts. Upgrading to v1.7.1 or newer removes the flaw.

Risk and Exploitability

The CVSS score of 7.5 indicates high severity, and the EPSS score is < 1%, indicating limited exploitation potential. The vulnerability can be exploited remotely over HTTP without authentication, making it readily actionable. An attacker can trigger memory exhaustion or CPU overload, causing the service to become unresponsive. Official remediation is available in the 1.7.1 release, and the vulnerability is not listed in CISA KEV.

Generated by OpenCVE AI on September 20, 2026 at 14:31 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Update the mcp-searxng server to version 1.7.1 or newer where the issue is fixed.
  • If an immediate upgrade is not feasible, restrict access to the web_url_read endpoint to trusted clients or require authentication to prevent unauthenticated exploitation.
  • As a temporary measure, configure the underlying HTTP server to reject or otherwise limit requests with missing Content-Length headers specifically for the web_url_read path if such configuration is supported.

Generated by OpenCVE AI on September 20, 2026 at 14:31 UTC.

Tracking

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Advisories

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History

Thu, 17 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
First Time appeared Ihor-sokoliuk
Ihor-sokoliuk mcp-searxng
Vendors & Products Ihor-sokoliuk
Ihor-sokoliuk mcp-searxng

Tue, 15 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 15 Sep 2026 18:00:00 +0000

Type Values Removed Values Added
Description mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.7.1, web_url_read in src/index.ts passes a caller-supplied URL to readUrlContent() in src/url-reader.ts, where checkContentLength() treats a missing Content-Length header as an inconclusive preflight and the normal and error paths then consume the complete body with response.text(). A server that omits Content-Length can therefore bypass URL_READ_MAX_CONTENT_LENGTH_BYTES and force unbounded memory use. The resulting string is also processed by NodeHtmlMarkdown.translate(), increasing CPU consumption and allowing an unauthenticated HTTP client to cause denial of service. This issue is fixed in version 1.7.1.
Title mcp-searxng: Unbounded Response Body Read Bypasses URL Size Limit in `web_url_read`
Weaknesses CWE-400
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'}

Subscriptions

Ihor-sokoliuk Mcp-searxng
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-15T18:25:34.075Z

Reserved: 2026-06-30T20:21:25.811Z

Link: CVE-2026-58483

cve-icon Vulnrichment

Updated: 2026-09-15T18:22:44.557Z

cve-icon NVD

Status : Deferred

Published: 2026-09-15T18:17:25.873

Modified: 2026-09-30T17:51:56.193

Link: CVE-2026-58483

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-20T14:45:06Z

Weaknesses
  • CWE-400

    Uncontrolled Resource Consumption