CVE-2026-101090
CriticalCVSS 9.8Summary
Nezha 2.2.3 contains a Host header injection regression in the OAuth2 redirect endpoint. When the dashboard_host setting is empty, /api/v1/oauth2/{provider} reflects the attacker-supplied Host header into the redirect_uri. An attacker can steal the victim's authorization code and take over the account.
Risk Assessment
Attackers can take over user accounts, potentially leading to unauthorized access to data and resources in the Nezha system.
Recommendation
Set dashboard_host to a fixed value or apply a patch if available. Until then, restrict trust in Host headers.
Other vulnerabilities in Nezha
See all- CVE-2026-101089Low
Nezha before 2.2.7 contains an information disclosure vulnerability in the GET /api/v1/profile endpoint that returns the bcrypt-hashed password field of authenticated users. Attackers can extract password hashes and perform offline cracking attacks without rate limiting or audit trail constraints.
- CVE-2026-101088Medium
Nezha is a server and website monitoring tool. In versions >= 2.2.11 and < 2.3.1, the service sentinel worker (service/singleton/servicesentinel.go) contains an incomplete fix for a previously reported nil dereference denial of service (GHSA-qjpp-gffx-2wm9). The 2026-07-21 fix re-validated the service lifecycle under serviceResponseDataStoreLock but reused an already-captured, now stale reporter pointer and never re-validated the server, and that lock does not guard ServerShared. An authenticated user with the member role who owns an agent can issue a concurrent server delete (POST /api/v1/batch-delete/server) for their own server to win the race window, causing the worker to dereference a missing entry in the server list snapshot. Because the sentinel workers and the gRPC server have no recover()/recovery interceptor, the resulting panic is unrecovered and crashes the entire instance. This is fixed in version 2.3.1.
- CVE-2026-101087Medium
Nezha versions 2.0.10 through 2.3.2 use a restricted HTTP client to validate user-configurable notification and DDNS webhook URLs, but the denylist did not cover IPv6 transition ranges — specifically the 6to4 prefix 2002::/16 and the local-use IPv4/IPv6 translation prefix 64:ff9b:1::/48. Because such addresses satisfy Go's netip.Addr.IsGlobalUnicast check, the URL validator accepted them. An authenticated user able to configure a webhook may be able to cause the dashboard to issue requests to an otherwise restricted IPv6 endpoint, but only where the dashboard's network provides unusual or non-standards-compliant routing for these transition ranges; no direct path to an IPv4 metadata, loopback, or private-network HTTP request has been demonstrated. The issue is fixed in version 2.3.3 (commit d1fcde8e), which blocks both prefixes.
- CVE-2026-101085Medium
Nezha before 2.3.8 fails to validate alert rule type and duration bounds, allowing authenticated non-administrator users to create malformed rules that trigger unrecovered panics in the alert evaluator goroutine. An attacker can submit a crafted rule via POST /api/v1/alert-rule, crashing the dashboard process.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS