Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. Prior to 2.2.5, the GET /api/v1/ddns and GET /api/v1/notification endpoints return full resource objects including plaintext third-party API credentials, including Cloudflare API tokens, TencentCloud SecretKeys, Slack, Discord, and Telegram webhook URLs with embedded bot tokens, and Authorization header values, without any field-level redaction. Any authenticated admin or PAT with nezha:ddns:read or nezha:notification:read scope can receive stored credentials through the listDDNS and listNotification handlers in a single API response. This issue is fixed in version 2.2.5.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the getRedirectURL function in oauth2.go:22-29 constructs the OAuth2 callback URL by concatenating the request's Host header with a fixed path, with zero validation of the Host header. This can result in host header injection. This issue has been patched in version 2.2.0.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 2.0.14 to before version 2.1.0, authenticated users can claim the dashboard Host through NAT and preempt all dashboard routing. This issue has been patched in version 2.1.0.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.2.0, the Nezha dashboard exposes two endpoints that create long-lived WebSocket streams to monitored agents: POST /api/v1/terminal → createTerminal() (terminal.go:27-67) and POST /api/v1/file → createFM() (fm.go:28-67). Both call rpc.NezhaHandlerSingleton.CreateStream(streamId, ...) which inserts a new ioStreamContext into an unbounded map[string]*ioStreamContext (s.ioStreams in io_stream.go:59-67). There is no per-user rate limit, no global semaphore, and no per-server connection cap. This issue has been patched in version 2.2.0.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.4.0 to before version 2.0.8, nezha's dashboard supports two user roles: RoleAdmin (Role==0) and RoleMember (Role==1). The notification routes POST /api/v1/notification and PATCH /api/v1/notification/:id are wired through commonHandler rather than adminHandler — so a RoleMember user can call them. These handlers synchronously Send() an HTTP request to a user-controlled URL and reflect the entire response body (no size limit) back to the caller on any non-2xx response. This issue has been patched in version 2.0.8.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 2.0.0 to before version 2.0.14, private services (`EnableShowInService: false`) are enumerable via per-server endpoints, leaking name and timing data. This issue has been patched in version 2.0.14.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 0.20.0 to before version 2.0.12, authenticated agents can forge service-monitor results for other users' services. This issue has been patched in version 2.0.12.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 1.0.0 to before version 2.0.14, cross-site GET request can trigger stored cron commands on a victim's agents. This issue has been patched in version 2.0.14.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 2.0.14 to before version 2.1.0, PATCH /server/{id} accepts and persists nonexistent ddns_profiles IDs for a member-owned server. If another user later creates a DDNS profile with one of those IDs, the DDNS worker resolves the stored ID and dispatches an update using the other user's DDNS profile configuration in the context of the attacker's server. This issue has been patched in version 2.1.0.

Nezha Monitoring is a self-hostable, lightweight, servers and websites monitoring and O&M tool. From version 0.20.0 to before version 2.0.10, an authenticated Nezha dashboard user can create or update a DDNS profile with provider webhook and configure an arbitrary webhook_url, HTTP method, request body, and headers. When DDNS is triggered for a server that uses that profile, the dashboard process sends the configured request with utils.HttpClient without the SSRF protections used by notification webhooks. This allows a low-privileged authenticated user who controls an owned server/DDNS profile to make the dashboard host issue HTTP requests to loopback or internal network services. The response body is not returned to the attacker in the confirmed path, so this is a blind SSRF / internal state-changing request primitive. This issue has been patched in version 2.0.10.