# CVE-2026-84856 — rowboatlabs rowboat

> As of 2026-09-03, CVE-2026-84856 is a MEDIUM-severity vulnerability in rowboatlabs rowboat, CVSS v3.1 5.3, EPSS 0.4% (33.7th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-84856 as of 2026-09-03; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-03

## What is CVE-2026-84856?

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.

The record classifies CVE-2026-84856 under weakness class [CWE-404](https://cwe.mitre.org/data/definitions/404.html). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 33 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 5.3 — MEDIUM (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C`)
- **CVSS v4.0 base score:** 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`)
- **EPSS (FIRST):** 0.4% probability of exploitation in the next 30 days, higher than 33.7% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-02, last modified 2026-09-03

## Is CVE-2026-84856 being exploited?

It currently carries a trending score of 38 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **rowboatlabs**: rowboat

## How to fix CVE-2026-84856

No vendor patch reference has been recorded for CVE-2026-84856 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-84856

No threat campaign in the Threadlinqs corpus currently references CVE-2026-84856, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, GitHub Security Advisories, FIRST EPSS. Last verified by Threadlinqs on 2026-09-04.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/rowboatlabs/rowboat/releases/tag/v0.9.2)

**Exploit and proof of concept**

- [github.com — exploit](https://github.com/hackerguopeng/cve/tree/main/Rowboat_PreAuth_Body_Buffer_DoS_Report)

**Technical analysis**

- [vuldb.com — vdb entry](https://vuldb.com/vuln/398131)

**Third-party advisory**

- [vuldb.com — signature](https://vuldb.com/vuln/398131/cti)
- [vuldb.com — third party advisory](https://vuldb.com/cve/CVE-2026-84856)
- [vuldb.com — third party advisory (886260)](https://vuldb.com/submit/886260)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-84856
Full detection coverage and IOCs for threats exploiting CVE-2026-84856 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp