CVE-2026-42260

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

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Published May 12, 2026 CVSS 3.1 · 8.2 High EPSS < 1% KEV · Not listed

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.

Analysis

Technical impact

Open‑WebSearch contains a vulnerability in the URL safety checks used by the fetchWebContent tool. The functions isPublicHttpUrl and assertPublicHttpUrl fail to reject bracketed IPv6 literals and do not perform DNS resolution, allowing an attacker to supply a crafted URL that the tool will resolve and fetch. The fetched content is returned to the caller, resulting in a non‑blind SSRF that can leak arbitrary data. This flaw is classified as CWE‑918.

Affected Systems

All installations of Aas‑ee open‑webSearch older than version 2.1.7 are affected. The issue exists in the MCP server, CLI, and local daemon components. Users running any pre‑2.1.7 release of this project are vulnerable.

Risk and Exploitability

The vulnerability has a CVSS score of 8.2 and is not listed in the CISA KEV catalog. EPSS data is not available, but the lack of DNS resolution and bracketed IPv6 support create an exploitation path that can be invoked remotely if the service is reachable from an attacker. Successful exploitation would grant the attacker the ability to read arbitrary resources and exfiltrate their content, potentially compromising sensitive information or internal infrastructure.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Aas-ee

open-webSearch

affected

Version	Status	Constraints
`< 2.1.7`	affected	—

No data.

Vendor Product Versions

Aas-ee

Open-websearch

Version	Status	Scheme	Platform
`[0,2.1.7)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade Open‑WebSearch to version 2.1.7 or later, which fixes the URL validation logic.
If an immediate upgrade is not possible, restrict the outbound network access of the fetchWebContent service by configuring firewall rules or host‑based rules to allow connections only to trusted IP ranges, limiting the potential impact of SSRF.
Monitor inbound requests to the fetchWebContent endpoint for suspicious URL patterns, such as bracketed IPv6 literals, and log or alert on attempts that do not appear legitimate.

Generated by OpenCVE AI on May 12, 2026 at 16:51 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-v228-72c7-fx8j	open-websearch has SSRF in `fetchWebContent` MCP tool: bracketed IPv6 literals and non-resolving hostname check bypass `isPrivateOrLocalHostname`

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact High

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.261% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

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

History

May 14, 2026 8:15 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

May 13, 2026 11:00 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Aas-ee Aas-ee open-websearch
Vendors & Products		Aas-ee Aas-ee open-websearch

May 12, 2026 3:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
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.
Title		Open-WebSearch: SSRF in `fetchWebContent` MCP tool: bracketed IPv6 literals and non-resolving hostname check bypass `isPrivateOrLocalHostname`
Weaknesses		CWE-918
References		https://github.com/Aas-ee/open-webSearch/security/advisories/GHSA-v228-72c7-fx8j
Metrics		cvssV3_1 `{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N'}`