Nezha through 2.2.3 Host Header Injection via OAuth2 redirect_uri
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Spoofing
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-601.
Summary
Nezha 2.2.3 contains a Host header injection regression in the OAuth2 redirect endpoint. When the new optional dashboard_host setting is empty, /api/v1/oauth2/{provider} (cmd/dashboard/controller/oauth2.go) reflects the attacker-supplied HTTP Host header into the redirect_uri sent to the identity provider instead of falling back to the configured install_host. An attacker who induces a victim to begin OAuth2 login via a request that reaches Nezha with a forged Host header can cause an attacker-controlled callback URL to be used as the redirect_uri; if the OAuth2 provider accepts it, the victim's authorization code is delivered to the attacker origin, allowing the attacker to complete the OAuth2 login/binding flow and take over the account. This regresses the fix for GHSA-9rc6-8cjv-rcvx and is configuration-dependent (dashboard_host empty). At the time of the advisory no patched version was available.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-101090
- 2026-10-03 Alias added: GHSA-62gj-x2f3-j2wj
References
More nezhahq vulnerabilities
- TI-2026-34341 Nezha Monitoring: RoleMember can run shell on every server (cross-tenant RCE) via POST /api/v1/cron CVSS 3.1CRITICAL 9.9
- TI-2026-34342 Nezha Monitoring: RoleMember-reachable SSRF with full response-body reflection via POST /api/v1/notification CVSS 3.1HIGH 7.7
- TI-2026-38597 Nezha Monitoring: OAuth2 Redirect URL — Host Header Injection CVSS 3.1MEDIUM 6.8
- TI-2026-75131 Memory exhaustion in Nezha file manager WebSocket endpoint CVSS 4.0HIGH 7.1
- TI-2026-75130 Nezha WebSocket transfer endpoint flaw enables denial of service CVSS 4.0HIGH 7.1
- TI-2026-67488 Nezha 1.8.0 before 2.3.13 Denial of Service via Notification Mutex Deadlock CVSS 4.0HIGH 7.1
Sources
- CVE-2026-101090 · CVE Program
- CVE-2026-101090 · NVD
- FIRST EPSS
- GHSA-62gj-x2f3-j2wj · GitHub Advisory Database · CC BY 4.0
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