# CVE-2026-65652: temporalio/tchannel-go malformed checksum type causes process termination

> Remote attackers can crash applications using the tchannel-go library by sending malformed checksum types, causing a denial of service.

- **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-2mhp-wpjp-pjr8

## What is CVE-2026-65652?

CVE-2026-65652 is a high-severity denial of service vulnerability in temporalio/tchannel-go, published on 21 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

github.com/temporalio/tchannel-go did not validate the one-byte checksum-type field in inbound TChannel call frames. A network peer that can reach a listener can complete the standard initialization handshake and send a call request with an unsupported checksum type. The parser uses that value as an index into a four-entry checksum pool, causing an unrecovered Go panic on the connection read goroutine and terminating the hosting process. This allows remote denial of service against applications that expose the listener to untrusted peers. The impact is limited to availability; no confidentiality or integrity impact was identified.

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

## Which versions are affected by CVE-2026-65652?


## How do I fix CVE-2026-65652?

No fix has been published for CVE-2026-65652 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-65652 being exploited?

There is no known exploitation of CVE-2026-65652 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-65652 and fix it if it is affected.

What it is: CVE-2026-65652 is a high-severity denial of service vulnerability in temporalio/tchannel-go, 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-2026-65652 in the wild and no public exploit code.

Affected product: temporalio/tchannel-go. 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-2026-65652/ (Markdown: https://insights.sbomify.com/CVE-2026-65652/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65652
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65652
- OSV: https://osv.dev/vulnerability/CVE-2026-65652

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-65652/
Summaries are generated and may contain mistakes; the official description above is the record.