# CVE-2026-101088: Nezha before 2.3.1 Denial of Service via Concurrent Server Delete

> An authenticated user can trigger a race condition during concurrent server deletion, causing an unrecovered panic that crashes the monitoring service.

- **Severity:** Medium 6.0 (`CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** GHSA-fqx6-jcw7-6879, GHSA-jx78-55p5-rwv5

## What is CVE-2026-101088?

CVE-2026-101088 is a medium-severity vulnerability in nezhahq nezha, published on 27 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-101088?


## How do I fix CVE-2026-101088?

No fix has been published for CVE-2026-101088 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-101088 being exploited?

There is no known exploitation of CVE-2026-101088 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-101088 and fix it if it is affected.

What it is: CVE-2026-101088 is a medium-severity vulnerability in nezhahq nezha, published on 27 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-101088 in the wild and no public exploit code.

Affected product: nezhahq nezha. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-101088/ (Markdown: https://insights.sbomify.com/CVE-2026-101088/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-101088
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-101088
- OSV: https://osv.dev/vulnerability/CVE-2026-101088

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-101088/
Summaries are generated and may contain mistakes; the official description above is the record.