CVE-2026-101090 Nezha through 2.2.3 Host Header Injection via OAuth2 redirect_uri
Attackers can hijack OAuth2 login flows by injecting a malicious Host header, leading to account takeover when the dashboard_host setting is empty.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-101090?
CVE-2026-101090 is a critical vulnerability in nezhahq nezha, published on 27 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-601
Which versions are affected by CVE-2026-101090?
3 open source packages ship an affected version, including github.com/nezhahq/nezha.
| Package | Affected | Fixed in |
|---|---|---|
github.com/nezhahq/nezha Go | All versions | None |
github.com/nezhahq/nezha Go | All versions | None |
github.com/nezhahq/nezha Go | All versions | None |
How do I fix CVE-2026-101090?
No fix has been published for CVE-2026-101090 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-101090 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-101090 exists.
Sources
Also known as GHSA-62gj-x2f3-j2wj, GHSA-rf68-8gjr-36q7, GO-2026-6486.