# CVE-2026-58483: mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.

Source: https://junglewise.ai/threats/cve-2026-58483-mcp-searxng-web-url-read-denial-of-service-via-unbounded-response  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-58483 · Severity: high · CVSS 7.5 · Published 2026-09-15

mcp-searxng is an MCP server that allows AI agents to fetch and read web content via the web_url_read tool. A remote attacker can force unbounded memory and CPU consumption by serving a web response without a Content-Length header, bypassing the tool's 5 MiB size limit and causing the server process to hang or crash, disrupting service availability for all users.

Technologies: [mcp-searxng (npm)](https://junglewise.ai/threats/technologies/mcp-searxng). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-58483 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-58483 being exploited in the wild.

**How severe is CVE-2026-58483?** High severity, with a CVSS score of 7.5, published 15 September 2026.

**Which products and versions are affected?** mcp-searxng (npm) SEMVER:introduced=0,fixed=1.7.1.

**Is there a fix for CVE-2026-58483?** Yes. mcp-searxng (npm): upgrade to 1.7.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-58483 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-58483?** Check whether you run mcp-searxng (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- mcp-searxng (npm): upgrade to 1.7.1 or later

  ```sh
  npm install mcp-searxng@1.7.1
  ```


## Technical details

This is an uncontrolled resource consumption (denial of service) vulnerability in the web_url_read MCP tool. The vulnerable code relies on a HEAD request to check the Content-Length header before fetching the full response body. However, when a server omits Content-Length—which is valid HTTP behavior—the checkContentLength() function returns null, causing the guard condition (contentLength !== null) to evaluate false and bypass the 5 MiB size check entirely. The subsequent GET request via response.text() then loads the unbounded response body into memory without any cap, amplified by CPU-intensive HTML-to-Markdown conversion. An unauthenticated attacker in HTTP transport mode (the default) can trigger this by supplying a URL to a malicious endpoint; in stdio mode, prompt injection can force the AI model to call the tool with an attacker-controlled URL. The vendor released patched version 1.7.1 addressing the issue by implementing streaming response reading with byte limits.

## Affected products

- ihor-sokoliuk mcp-searxng <=1.6.0

## Identifiers

- CVE-2026-58483
- GHSA-xcqx-9jf5-w339

## Timeline

- 2026-06-18: disclosed
- 2026-06-19: patched: Version 1.7.1 released with streaming response reader fix

## References

- [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)
- [https://github.com/ihor-sokoliuk/mcp-searxng](https://github.com/ihor-sokoliuk/mcp-searxng)

## Related threats

- [mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.](https://junglewise.ai/threats/cve-2026-58485-mcp-searxng-web-url-read-dns-rebinding-ssrf)
- [mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.](https://junglewise.ai/threats/cve-2026-54689-searxng-mcp-server-hardened-mode-ssrf-bypass-via-redirect-and)
- [mcp-searxng is a Model Context Protocol server that gives AI assistants web search and URL-reading capabilities through SearXNG. Prior to 1.](https://junglewise.ai/threats/cve-2026-54688-searxng-mcp-server-ssrf-in-web-url-read)
- [mcp-searxng credentials exposure in logging and error handling](https://junglewise.ai/threats/mcp-searxng-credentials-exposure-in-logging-and-error-handling-ad6f8cfd)