Nezha Monitoring Host Header Injection Vulnerability

Publication date: 2026-06-12

Last updated on: 2026-06-15

Assigner: GitHub, Inc.

Description

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-06-12

Last Modified

2026-06-15

Generated

2026-07-03

AI Q&A

2026-06-13

EPSS Evaluated

2026-07-02

NVD

CVE-2026-53523

Affected Vendors & Products

Vendor	Product	Version / Range
nezha_monitoring	nezha_monitoring	From 1.0.0 (inc) to 2.2.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-601	The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Nezha Monitoring versions from 1.0.0 up to but not including 2.2.0. It involves the getRedirectURL function in the oauth2.go file, which constructs the OAuth2 callback URL by concatenating the Host header from the request with a fixed path without validating the Host header. This lack of validation allows an attacker to perform host header injection.

Impact Analysis

The vulnerability can lead to host header injection, which may allow attackers to manipulate the OAuth2 callback URL. This can result in unauthorized redirection or interception of OAuth2 authentication flows, potentially compromising confidentiality and integrity of user authentication. According to the CVSS score of 6.8, the impact includes high confidentiality and integrity loss, though availability is not affected.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade Nezha Monitoring to version 2.2.0 or later, where the host header injection issue has been patched.

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