# CVE-2026-84856: rowboatlabs rowboat Composio Webhook Endpoint route.ts req.json denial of service

> Remote attackers can cause denial of service in Rowboat via the Composio Webhook Endpoint by exploiting improper request handling.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-66mr-2w7f-r56j

## What is CVE-2026-84856?

CVE-2026-84856 is a medium-severity denial of service vulnerability in rowboatlabs rowboat, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability was detected in rowboatlabs rowboat up to 0.9.1. The impacted element is the function request.text/req.json of the file apps/rowboat/app/api/composio/webhook/route.ts of the component Composio Webhook Endpoint. The manipulation results in denial of service. It is possible to launch the attack remotely. The exploit is now public and may be used. Upgrading to version 0.9.2 is sufficient to resolve this issue. Upgrading the affected component is recommended. The legacy Next.js app was deleted at 0.9.2 rather than patched, leaving no security control behind.

Weakness: CWE-404 (Improper Resource Shutdown or Release)

## Which versions are affected by CVE-2026-84856?


## How do I fix CVE-2026-84856?

No fix has been published for CVE-2026-84856 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-84856 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-84856 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-84856 and fix it if it is affected.

What it is: CVE-2026-84856 is a medium-severity denial of service vulnerability in rowboatlabs rowboat, published on 2 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-84856 exists.

Affected product: rowboatlabs rowboat. 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-2026-84856/ (Markdown: https://insights.sbomify.com/CVE-2026-84856/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-84856
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-84856
- OSV: https://osv.dev/vulnerability/CVE-2026-84856

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-84856/
Summaries are generated and may contain mistakes; the official description above is the record.