EUVD-2026-36602
GHSA-9rc6-8cjv-rcvx
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
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. A vendor-released patch exists in version 2.2.0; no public exploit has been identified at time of analysis and the vulnerability is not in the CISA KEV catalog.
Technical ContextAI
The vulnerability is rooted in Nezha Monitoring's OAuth2 authentication subsystem, specifically in the getRedirectURL function at oauth2.go lines 22-29. When a user initiates an OAuth2 login flow, the application constructs the redirect/callback URL by string-concatenating the HTTP Host header - which is fully attacker-controllable in direct-exposure deployments - with a fixed path suffix. No server-side validation, allowlisting, or canonicalization of the Host header value is applied before this concatenation. CWE-601 (URL Redirection to Untrusted Site / Open Redirect) describes the root cause class: user-supplied input directly influences a redirect destination without validation. The affected CPE is cpe:2.3:a:nezhahq:nezha:*:*:*:*:*:*:*:* covering all releases from 1.0.0 to before 2.2.0. HTTP Host header injection is a well-documented attack class commonly exploited in password-reset poisoning and OAuth flow hijacking, and is particularly effective in self-hosted tools where operators may not deploy a reverse proxy that canonicalizes the Host header.
RemediationAI
Vendor-released patch: version 2.2.0. Upgrade to Nezha Monitoring 2.2.0 or later immediately; this release introduces Host header validation in the OAuth2 callback URL construction and is the definitive fix. Details are available at https://github.com/nezhahq/nezha/security/advisories/GHSA-9rc6-8cjv-rcvx. If immediate patching is not possible, deploy Nezha behind a reverse proxy (nginx, Caddy, or Traefik) configured to explicitly set and enforce the canonical Host header - for example, using nginx's proxy_set_header Host directive with a hardcoded value - which prevents attacker-supplied Host headers from reaching the application entirely; note this mitigates the injection but does not fix the underlying code. As an additional control, temporarily disabling OAuth2 authentication and reverting to an alternate login method eliminates the vulnerable code path at the cost of SSO functionality. Restricting access to the Nezha dashboard to trusted network ranges via firewall rules reduces the pool of potential attackers able to deliver the crafted OAuth link.
More in Open Redirect
View allA malicious third-party can give a crafted "ssh://..." URL to an unsuspecting victim, and an attempt to visit the URL ca
GFI Kerio Control versions 9.2.5 through 9.4.5 contain an HTTP response splitting vulnerability in the dest parameter of
PHP through 7.0.8 does not attempt to address RFC 3875 section 4.1.18 namespace conflicts and therefore does not protect
Multiple open redirect vulnerabilities in Apache Struts 2.0.0 through 2.3.15 allow remote attackers to redirect users to
Open redirect vulnerability in age-verification.php in the Age Verification plugin 0.4 and earlier for WordPress allows
Open redirect vulnerability in Kaseya Virtual System Administrator (VSA) 7.x before 7.0.0.29, 8.x before 8.0.0.18, 9.0 b
Vulnerability in the Oracle Applications Framework component of Oracle E-Business Suite (subcomponent: Popup windows (li
Unspecified vulnerability in the Oracle Application Server Single Sign-On component in Oracle Fusion Middleware 10.1.4.3
Flarum is open source discussion platform software. Rated medium severity (CVSS 6.5), this vulnerability is remotely exp
Open redirect vulnerability in Novius OS 5.0.1 (Elche) allows remote attackers to redirect users to arbitrary web sites
Open redirect vulnerability in the Redirect function in stageshow_redirect.php in the StageShow plugin before 5.0.9 for
Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link. Rated crit
Vendor StatusVendor
SUSE
Severity: Moderate| Product | Status |
|---|---|
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
Share
External POC / Exploit Code
Leaving vuln.today