CVE-2026-42260 PUBLISHED

Open-WebSearch: SSRF in `fetchWebContent` MCP tool: bracketed IPv6 literals and non-resolving hostname check bypass `isPrivateOrLocalHostname`

Assigner: GitHub_M
Reserved: 26.04.2026 Published: 12.05.2026 Updated: 12.05.2026

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.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
CVSS Score: 8.2

Attack Vector	Network	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	Low
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	Aas-ee
Product	open-webSearch
Versions	Version < 2.1.7 is affected

References

https://github.com/Aas-ee/open-webSearch/security/advisories/GHSA-v228-72c7-fx8j

Problem Types

CWE-918: Server-Side Request Forgery (SSRF) CWE