Vulnerability · Published Sep 27, 2026 · Assigned by VulnCheck
CVE-2026-101090Nezha through 2.2.3 Host Header Injection via OAuth2 redirect_uri
Critical 9.8
In plain English
A critical-severity open redirect in nezha from nezhahq. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 39% of all known vulnerabilities).
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/nezhahq/nezha | no fix listed | GHSA-rf68-8gjr-36q7 |
| Go | github.com/nezhahq/nezha | no fix listed | GO-2026-6486 |
Affected products (as reported)
Weakness: CWE-601 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- GitHub Security Advisory (GHSA-rf68-8gjr-36q7) vendor-advisory
- VulnCheck Advisory: Nezha through 2.2.3 Host Header Injection via OAuth2 redirect_uri third-party-advisory