# CVE-2026-16651: temporalio/sqlparser malformed MySQL version comments can cause a panic

> An authenticated attacker can cause a denial of service in Temporal Server by submitting malformed SQL queries that trigger a parser panic.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 21 Sep 2026
- **Updated:** 21 Sep 2026
- **Also known as:** GHSA-g9jq-gq4v-4rw3

## What is CVE-2026-16651?

CVE-2026-16651 is a high-severity denial of service vulnerability in Temporal Server, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

temporalio/sqlparser can panic when Parse, ParseStrictDDL, or ParseNext processes a MySQL version comment whose contents are empty or consist only of one to five decimal digits. ExtractMysqlComment does not check the -1 result returned by strings.IndexFunc before using it as a slice boundary. The resulting Go runtime panic propagates unless the caller recovers it on the parsing goroutine, so applications that parse attacker-controlled SQL can terminate. Temporal Server exposes the affected parser through ListWorkers. When that API is enabled, an authenticated caller with namespace read permission can submit a malformed query that terminates the receiving Matching process. Repeated requests can sustain a denial of service. The issue affects availability only; no confidentiality or integrity impact was identified.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-16651?


## How do I fix CVE-2026-16651?

No fix has been published for CVE-2026-16651 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-16651 being exploited?

There is no known exploitation of CVE-2026-16651 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-16651 and fix it if it is affected.

What it is: CVE-2026-16651 is a high-severity denial of service vulnerability in Temporal Server, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-16651 in the wild and no public exploit code.

Affected product: Temporal Server. 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-2026-16651/ (Markdown: https://insights.sbomify.com/CVE-2026-16651/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-16651
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-16651
- OSV: https://osv.dev/vulnerability/CVE-2026-16651

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-16651/
Summaries are generated and may contain mistakes; the official description above is the record.