# CVE-2026-100394: Nezha Monitoring: Whole-instance DoS in Nezha dashboard: a member can crash the process for every tenant

> A race condition allows a member to crash the entire Nezha Monitoring dashboard process, denying service to all tenants.

- **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:** 14 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-qjpp-gffx-2wm9, GO-2026-6794

## What is CVE-2026-100394?

CVE-2026-100394 is a medium-severity vulnerability in nezhahq nezha, published on 14 Oct 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 2.2.7 until 2.2.11, ServiceSentinel.worker in service/singleton/servicesentinel.go checked an owned service under servicesLock and later dereferenced pointer-valued serviceStatusToday and serviceCurrentStatusData entries under serviceResponseDataStoreLock without revalidating that ServiceSentinel.Delete had not removed them. A RoleMember could concurrently report TCP or ICMP results through the member's own agent and delete the same owned service, causing a nil pointer dereference. Because the gRPC server had no recovery interceptor, the worker panic terminated the whole dashboard process and disrupted every tenant's web interface, REST API, and agent connections. The issue affects availability only and does not disclose or modify data. This issue is fixed in versions 2.2.11 and 2.3.0.

Weakness: CWE-476 (NULL Pointer Dereference), CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-100394?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/nezhahq/nezha` | Go | From 0.0.0-20260628010923-fd31e5f1b0f8 | 0.0.0-20260721131105-c893aa57867d |
| `github.com/nezhahq/nezha` | Go | From 0.0.0-20260628010923-fd31e5f1b0f8 | 0.0.0-20260721131105-c893aa57867d |
| `github.com/nezhahq/nezha` | Go | From 0.0.0-20260628010923-fd31e5f1b0f8 | 0.0.0-20260721131105-c893aa57867d |

## How do I fix CVE-2026-100394?

Upgrade github.com/nezhahq/nezha to 0.0.0-20260721131105-c893aa57867d or later.

## Is CVE-2026-100394 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-100394 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-100394 and fix it if it is affected.

What it is: CVE-2026-100394 is a medium-severity vulnerability in nezhahq nezha, published on 14 Oct 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-2026-100394 exists.

Affected packages and fixed versions:
- github.com/nezhahq/nezha (Go): affected from 0.0.0-20260628010923-fd31e5f1b0f8; fixed in 0.0.0-20260721131105-c893aa57867d
- github.com/nezhahq/nezha (Go): affected from 0.0.0-20260628010923-fd31e5f1b0f8; fixed in 0.0.0-20260721131105-c893aa57867d
- github.com/nezhahq/nezha (Go): affected from 0.0.0-20260628010923-fd31e5f1b0f8; fixed in 0.0.0-20260721131105-c893aa57867d

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-2026-100394/ (Markdown: https://insights.sbomify.com/CVE-2026-100394/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-100394
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-100394
- OSV: https://osv.dev/vulnerability/CVE-2026-100394

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-100394/
Summaries are generated and may contain mistakes; the official description above is the record.