# CVE-2026-65654: temporalio/ringpop-go fails to enforce configured label limits on inbound membership gossip

> A remote attacker can exhaust memory and bandwidth by sending oversized label maps in SWIM gossip, causing denial of service in applications using ringpop-go.

- **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-2cw5-f255-55f8

## What is CVE-2026-65654?

CVE-2026-65654 is a high-severity denial of service vulnerability in temporalio/ringpop-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/ringpop-go enforces configured LabelOptions limits when an application changes the local node's labels, but affected versions do not apply those limits to label maps received in SWIM membership changes. A network peer that can reach a live Ringpop TChannel listener can repeatedly submit changes for distinct member addresses containing label keys, values, or counts that exceed the receiver's configured limits. Accepted labels are retained in the member list and disseminated to peers, allowing memory and gossip-bandwidth consumption to exceed configured bounds and potentially making the hosting process unavailable. The fix validates peer-supplied label maps before they are retained or disseminated. Availability only; no confidentiality or integrity impact was identified.

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

## Which versions are affected by CVE-2026-65654?


## How do I fix CVE-2026-65654?

No fix has been published for CVE-2026-65654 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-65654 being exploited?

There is no known exploitation of CVE-2026-65654 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-65654 and fix it if it is affected.

What it is: CVE-2026-65654 is a high-severity denial of service vulnerability in temporalio/ringpop-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-2026-65654 in the wild and no public exploit code.

Affected product: temporalio/ringpop-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-2026-65654/ (Markdown: https://insights.sbomify.com/CVE-2026-65654/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-65654
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-65654
- OSV: https://osv.dev/vulnerability/CVE-2026-65654

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-65654/
Summaries are generated and may contain mistakes; the official description above is the record.