{"id":"CVE-2026-101090","published":"2026-09-27T21:17:03.003","lastModified":"2026-09-28T21:02:16.150","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.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-601"],"vendors":[],"products":[],"references":[{"url":"https://github.com/nezhahq/nezha/security/advisories/GHSA-rf68-8gjr-36q7","tags":[]},{"url":"https://www.vulncheck.com/advisories/nezha-through-2.2.3-host-header-injection-via-oauth2-redirect-uri","tags":[]},{"url":"https://github.com/nezhahq/nezha/security/advisories/GHSA-rf68-8gjr-36q7","tags":[]}],"exploitRefs":[{"url":"https://github.com/nezhahq/nezha/security/advisories/GHSA-rf68-8gjr-36q7","tags":[]},{"url":"https://github.com/nezhahq/nezha/security/advisories/GHSA-rf68-8gjr-36q7","tags":[]}],"hasPoc":true,"ai":{"summary":"The flaw allows an attacker to inject a Host header, leading to a redirect_uri that can be controlled, potentially enabling unauthorized account access.","exploitability":"Exploitation is relatively straightforward if an attacker can induce a victim to initiate the OAuth2 login process with a forged Host header.","blast_radius":"If exploited, the attacker can take over the victim's account, leading to significant data and account compromise.","remediation":"Upgrade to Nezha 2.2.4 or later.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["auth-bypass","web","oauth2","header-injection"],"model":"qwen2.5:7b-instruct","analyzedAt":"2026-09-28T08:48:39.793Z"}}