# CVE-2026-53522: Nezha Monitoring: Unbounded WebSocket Streams — Resource Exhaustion DoS

> Attackers can exhaust server resources by creating unlimited WebSocket streams via unbounded endpoints, causing denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jun 2026
- **Updated:** 15 Jun 2026
- **Also known as:** GHSA-jg62-j5h6-8mpq, GO-2026-5831

## What is CVE-2026-53522?

CVE-2026-53522 is a medium-severity denial of service vulnerability in nezhahq nezha, published on 12 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-53522?

3 open source packages ship an affected version, including github.com/nezhahq/nezha.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/nezhahq/nezha` | Go | From 1.0.0 | None |
| `github.com/nezhahq/nezha` | Go | From 1.0.0 | 2.2.0 |
| `github.com/nezhahq/nezha` | Go | From 1.0.0 | 2.2.0 |

## How do I fix CVE-2026-53522?

Upgrade github.com/nezhahq/nezha to 2.2.0 or later.

## Is CVE-2026-53522 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53522 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53522 and fix it if it is affected.

What it is: CVE-2026-53522 is a medium-severity denial of service vulnerability in nezhahq nezha, published on 12 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53522 exists.

Affected packages and fixed versions:
- github.com/nezhahq/nezha (Go): affected from 1.0.0; no fix listed
- github.com/nezhahq/nezha (Go): affected from 1.0.0; fixed in 2.2.0
- github.com/nezhahq/nezha (Go): affected from 1.0.0; fixed in 2.2.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-53522/ (Markdown: https://insights.sbomify.com/CVE-2026-53522/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53522
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53522
- OSV: https://osv.dev/vulnerability/CVE-2026-53522

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53522/
Summaries are generated and may contain mistakes; the official description above is the record.