CVE-2026-53522
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedNezha 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceNezha Monitoring dashboard versions 1.0.0 through 2.1.x expose two endpoints (/api/v1/terminal and /api/v1/file) that create long-lived WebSocket streams to monitored agents. These endpoints call CreateStream() which inserts into an unbounded map (s.ioStreams) without any rate limiting, global semaphore, or per-server connection cap. An attacker can exhaust server resources by initiating numerous concurrent WebSocket connections.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if Nezha Monitoring is runningCheck running processes or services for 'nezha' or examine active network listeners on common web ports (80, 443, 8080). Use commands like 'ps aux | grep -i nezha' or 'netstat -tlnp | grep -i listen' to locate the service.Affected if Nezha Monitoring dashboard is installed and running on the system
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Determine the installed Nezha versionCheck the version of Nezha Monitoring by examining the binary, container tag, or the application itself. If the dashboard is accessible, log in and check the about page or version information typically found in admin settings or the footer.Affected if The installed version falls within 1.0.0 through 2.1.x (any version before 2.2.0)
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Verify WebSocket endpoint exposureTest if the vulnerable endpoints are accessible by attempting WebSocket connections to /api/v1/terminal and /api/v1/file. Use a WebSocket client or curl with upgrade headers to probe these paths: 'curl -i -N -H "Connection: Upgrade" -H "Upgrade: websocket" https://YOUR_NEZHA_HOST/api/v1/terminal'.Affected if Either /api/v1/terminal or /api/v1/file endpoints respond and accept WebSocket upgrades
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Check for connection rate limitingExamine any reverse proxy (nginx, HAProxy, traefik) or load balancer in front of Nezha for rate limiting rules or connection caps applied to the WebSocket endpoints. Review proxy configuration files for limits on connections, requests, or WebSocket upgrade requests.Affected if No rate limiting, connection throttling, or per-server caps are configured on the proxy layer for these endpoints
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Monitor WebSocket connection countObserve the number of concurrent WebSocket connections to the Nezha server during normal operation. Use netstat or ss to count established WebSocket connections: 'ss -tn | grep -E "(ws|8080|80)"' or check application logs for connection metrics.Affected if Connection counts grow unbounded without apparent limits, or the server shows high resource usage from numerous concurrent WebSocket streams
A user is affected if Nezha Monitoring versions 1.0.0 to 2.1.x are running, the /api/v1/terminal or /api/v1/file endpoints are exposed, and no rate limiting or connection caps exist at the proxy level.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade to version 2.2.0 or later. If immediate patching is not feasible, implement rate limiting and connection caps at the reverse proxy or load balancer level as a compensating control.
2.2.0
- 1. Identify the current Nezha Monitoring version currently deployed
- 2. If the current version is between 1.0.0 and 2.1.x (inclusive), plan for upgrade
- 3. Review Nezha Monitoring upgrade documentation for your deployment method (Docker, binary, etc.)
- 4. Backup current configuration and data
- 5. Upgrade to version 2.2.0 or later
- 6. Verify the WebSocket endpoints now enforce proper resource limits
- 7. Monitor system resource usage to confirm the resource exhaustion issue is resolved
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-53522 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-53522 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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