# CVE-2026-53523: Nezha Monitoring Host Header Injection in OAuth2 callback

Source: https://junglewise.ai/threats/cve-2026-53523-nezha-monitoring-host-header-injection-in-oauth2-callback  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-12. Updated: 2026-06-26  
License: CC BY 4.0 with a link back

CVE-2026-53523 · Severity: medium · CVSS 6.8 · Published 2026-06-12

Nezha Monitoring, a dashboard for managing servers, is vulnerable to a security flaw in its login process. An attacker can trick a user into clicking a malicious link that redirects their login credentials to a server controlled by the attacker. This could allow the attacker to take over the user's account, potentially gaining full administrative control over all monitored servers and sensitive configuration data.

Technologies: [github.com/nezhahq/nezha (Go)](https://junglewise.ai/threats/technologies/github-com-nezhahq-nezha), [NezhaHQ Nezha Monitoring](https://junglewise.ai/threats/technologies/nezha). Vendors: [Go](https://junglewise.ai/threats/vendors/go), [NezhaHQ](https://junglewise.ai/threats/vendors/nezhahq).

## Quick answers

**Is CVE-2026-53523 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-53523 being exploited in the wild.

**How severe is CVE-2026-53523?** Medium severity, with a CVSS score of 6.8, published 12 June 2026.

**Which products and versions are affected?** github.com/nezhahq/nezha (Go) >= 1.0.0, < 2.2.0, SEMVER:introduced=1.0.0, SEMVER:introduced=1.0.0,fixed=2.2.0; NezhaHQ Nezha Monitoring >= 1.0.0, < 2.2.0; NezhaHQ Nezha Monitoring Dashboard >= 1.0.0, < 2.2.0.

**Is there a fix for CVE-2026-53523?** Yes. github.com/nezhahq/nezha (Go): upgrade to 2.2.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-53523 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-53523?** Check whether you run github.com/nezhahq/nezha (Go), NezhaHQ Nezha Monitoring or NezhaHQ Nezha Monitoring Dashboard at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/nezhahq/nezha (Go): upgrade to 2.2.0 or later

  ```sh
  go get github.com/nezhahq/nezha@v2.2.0
  ```


## Technical details

A Host Header Injection vulnerability exists in the `getRedirectURL` function within `cmd/dashboard/controller/oauth2.go`. The application constructs the OAuth2 callback URL using the unvalidated `Host` header from the incoming HTTP request. By crafting a request with a malicious `Host` header and inducing a victim to initiate OAuth2 authentication, an attacker can cause the OAuth2 provider to send the authorization code to an attacker-controlled domain. This code can then be exchanged for an access token, leading to account takeover. The vulnerability is mitigated by the requirement for user interaction and the need for the OAuth2 provider to have loose redirect URI validation (e.g., wildcard support). The issue is fixed in version 2.2.0 by using a deterministic configured base URL.

## Affected products

- nezhahq Nezha Monitoring Dashboard >= 1.0.0, < 2.2.0

## Identifiers

- CVE-2026-53523
- GHSA-9rc6-8cjv-rcvx
- GO-2026-5829

## Timeline

- 2026-06-05: disclosed
- 2026-06-12: advisory: NVD publication date
- 2026-06-26: patched: GitHub Advisory reviewed and updated

## References

- [https://api.github.com/users/alcls01111](https://api.github.com/users/alcls01111)
- [https://github.com/alcls01111](https://github.com/alcls01111)
- [https://api.github.com/users/alcls01111/gists%7B/gist_id%7D](https://api.github.com/users/alcls01111/gists%7B/gist_id%7D)
- [https://api.github.com/users/alcls01111/repos](https://api.github.com/users/alcls01111/repos)
- [https://avatars.githubusercontent.com/u/57210489?v=4](https://avatars.githubusercontent.com/u/57210489?v=4)
- [https://api.github.com/users/alcls01111/events%7B/privacy%7D](https://api.github.com/users/alcls01111/events%7B/privacy%7D)

## Related threats

- [Nezha monitoring dashboard denial of service via service deletion race](https://junglewise.ai/threats/cve-2026-100394-nezha-monitoring-whole-instance-dos-in-nezha-dashboard-a-member)
- [Nezha Host header injection in OAuth2 redirect endpoint](https://junglewise.ai/threats/cve-2026-101090-nezha-2-2-3-contains-a-host-header-injection-regression-in-the)
- [Nezha OAuth2 redirect_uri Host header injection regression](https://junglewise.ai/threats/nezha-oauth2-redirect-uri-host-header-injection-regression-331e924a)
- [Nezha Monitoring insufficient stream authorization in websocket endpoints](https://junglewise.ai/threats/cve-2026-62283-nezha-monitoring-insufficient-stream-authorization-in-websocket)
- [Nezha Monitoring plaintext credential exposure in DDNS and Notification APIs](https://junglewise.ai/threats/cve-2026-59155-nezha-monitoring-plaintext-credential-exposure-in-ddns-and)