CVE-2026-58483 mcp-searxng: Unbounded Response Body Read Bypasses URL Size Limit in `web_url_read`
An unauthenticated attacker can cause denial of service by forcing unbounded memory and CPU consumption via a crafted URL response in the mcp-searxng library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58483?
CVE-2026-58483 is a high-severity denial of service vulnerability in ihor-sokoliuk mcp-searxng, published on 15 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-400
Which versions are affected by CVE-2026-58483?
2 open source packages ship an affected version, including mcp-searxng.
| Package | Affected | Fixed in |
|---|---|---|
mcp-searxng npm | All versions | 1.7.1 |
mcp-searxng npm | All versions | 1.7.1 |
How do I fix CVE-2026-58483?
Upgrade mcp-searxng to 1.7.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-58483 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58483 exists.
Sources
Also known as GHSA-xcqx-9jf5-w339.