Severity by source
AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Network vector with high complexity for Host header manipulation; no privileges required but victim must complete OAuth flow for token exfiltration.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
Lifecycle Timeline
2DescriptionCVE.org
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.
AnalysisAI
Host header injection in Nezha Monitoring versions 1.0.0 through 2.2.0 allows unauthenticated remote attackers to redirect OAuth2 callback URLs to attacker-controlled domains, enabling OAuth token theft and account takeover. The flaw resides in the getRedirectURL function (oauth2.go:22-29), which blindly concatenates the HTTP request's Host header with a fixed path when constructing the OAuth2 redirect URL, with no allowlisting or validation performed. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires three concurrent conditions: (1) The target Nezha Monitoring instance must have OAuth2 authentication configured and enabled - instances using only local/password authentication do not exercise the vulnerable getRedirectURL code path. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The NVD CVSS 3.1 score of 6.8 with vector AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N represents a moderate-to-high real-world risk under the right deployment conditions. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker targeting a Nezha instance with OAuth2 enabled and no Host-normalizing reverse proxy crafts a link to the instance's OAuth2 initiation endpoint, ensuring the HTTP Host header is set to an attacker-controlled domain. The attacker socially engineers a Nezha administrator - via email, messaging, or a watering-hole page - into clicking the link and completing the OAuth2 login flow; the OAuth authorization code or token is then delivered to the attacker's server, granting full account access. … |
| Remediation | Vendor-released patch: version 2.2.0. … Detailed patch versions, workarounds, and compensating controls in full report. |
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EUVD-2026-36602