CVE-2026-61704
Received Received - Intake

Link Preview JS DNS Rebinding SSRF Bypass

Publication date: 2026-08-20

Last updated on: 2026-08-20

Assigner: GitHub, Inc.

Description
Link Preview JS extracts web links information. Prior to 4.0.4, the resolveDNSHost mitigation in index.ts validates one resolved IP address but fetches the original hostname, allowing an attacker-controlled DNS server to return a public address during validation and a loopback or internal address during the final connection. This DNS rebinding condition bypasses the SSRF protection and can cause the server-side preview fetch to reach internal HTTP resources. Redirect handling is affected by the same validation-to-fetch mismatch. This issue is fixed in version 4.0.4.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-08-20
Last Modified
2026-08-20
Generated
2026-08-20
AI Q&A
2026-08-20
EPSS Evaluated
N/A
NVD
CVE-2026-61704
EUVD
EUVD-2026-63439

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
link_preview_js link_preview_js 4.0.4
op-engineering link-preview-js to 4.0.4 (exc)

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

Link Preview JS before version 4.0.4 has a DNS rebinding vulnerability in its SSRF protection. The resolveDNSHost function validates one resolved IP but uses the original hostname for the final connection. An attacker can exploit this by returning a public IP during validation and a loopback or internal IP during the actual fetch, bypassing SSRF protection and accessing internal HTTP resources. Redirect handling is also affected by the same issue.

Detection Guidance

This vulnerability involves DNS rebinding where an attacker manipulates DNS responses to bypass SSRF protection. Detection requires monitoring DNS queries and responses for inconsistencies between resolved IPs and expected hostnames. Check if your system uses Link Preview JS versions prior to 4.0.4. Inspect network logs for unexpected internal or loopback address resolutions during external link previews.

Impact Analysis

This vulnerability allows an attacker to trick the server into making unauthorized internal HTTP requests. If exploited, it could lead to exposure of sensitive internal resources, data leaks, or further attacks against internal systems. Servers using affected versions may unknowingly fetch and process malicious or confidential internal content.

Compliance Impact

This vulnerability could lead to unauthorized access to internal systems and data, violating confidentiality requirements in GDPR and HIPAA. If exploited, it may result in data breaches, unauthorized data exposure, or unauthorized system access, all of which are compliance violations under these regulations.

Mitigation Strategies

Upgrade Link Preview JS to version 4.0.4 or later to address the DNS rebinding flaw. If immediate upgrade is not possible, implement network-level mitigations such as blocking outbound connections to internal or loopback addresses from the application. Review and restrict DNS resolution policies to prevent attacker-controlled DNS responses.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-61704. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart