# 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.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 15 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** GHSA-xcqx-9jf5-w339

## 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 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-58483?

2 open source packages ship an affected version, including mcp-searxng.


| Package | Ecosystem | 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.

## Is CVE-2026-58483 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58483 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-58483 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58483 exists.

Affected packages and fixed versions:
- mcp-searxng (npm): affected all versions; fixed in 1.7.1
- mcp-searxng (npm): affected all versions; fixed in 1.7.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-58483/ (Markdown: https://insights.sbomify.com/CVE-2026-58483/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-58483
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-58483
- OSV: https://osv.dev/vulnerability/CVE-2026-58483

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-58483/
Summaries are generated and may contain mistakes; the official description above is the record.