CVE-2026-42260 open-websearch has SSRF in `fetchWebContent` MCP tool: bracketed IPv6 literals and non-resolving hostname check bypass `isPrivateOrLocalHostname`
An attacker can bypass SSRF protections in Open-WebSearch to access internal resources via bracketed IPv6 literals or non-resolving hostnames.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42260?
CVE-2026-42260 is a high-severity server-side request forgery vulnerability in Aas-ee open-webSearch, published on 12 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Open-WebSearch is a multi-engine MCP server, CLI, and local daemon for agent web search and content retrieval. Prior to 2.1.7, isPublicHttpUrl / assertPublicHttpUrl in src/utils/urlSafety.ts do not recognize bracketed IPv6 literals and do not resolve DNS, which combine to allow non-blind SSRF with the response body returned to the caller. This vulnerability is fixed in 2.1.7.
Weakness: CWE-918
Which versions are affected by CVE-2026-42260?
2 open source packages ship an affected version, including open-websearch.
| Package | Affected | Fixed in |
|---|---|---|
open-websearch npm | All versions | 2.1.7 |
open-websearch npm | All versions | 2.1.7 |
How do I fix CVE-2026-42260?
Upgrade open-websearch to 2.1.7 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-42260 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-42260 exists.
Sources
Also known as GHSA-v228-72c7-fx8j.