What’s Vulnerable › Vulnerabilities

CVE-2026-58483: mcp-searxng: Unbounded Response Body Read Bypasses URL Size Limit in `web_url_read`

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-15 · updated 2026-09-30
• Weakness: CWE-400

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.

Affected products

• ihor-sokoliuk mcp-searxng: before 1.7.1

References

• https://github.com/ihor-sokoliuk/mcp-searxng/commit/f5a947ed1650daed10fbdcd53c0db5a86489ffe4
• https://github.com/ihor-sokoliuk/mcp-searxng/pull/121
• https://github.com/ihor-sokoliuk/mcp-searxng/releases/tag/v1.7.1
• https://github.com/ihor-sokoliuk/mcp-searxng/security/advisories/GHSA-xcqx-9jf5-w339
• https://github.com/ihor-sokoliuk/mcp-searxng/security/advisories/GHSA-xcqx-9jf5-w339

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