---
id: CVE-2026-63198
title: 'traQ: Privilege escalation by OAuth prompt=none request'
summary: >-
  traQ is a messenger application built for Digital Creators Club traP. Prior to
  3.28.3, OAuth2 silent authorization requests using prompt=none with an empty
  or omitted scope parameter check prior consent against the empty requested
  scope …
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N'
cvssSource: cna
cwe:
  - CWE-863
vendor: traPtitech
product: traQ
affected:
  - traQ < 3.28.3
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-11-03T19:37:34.520607Z'
published: '2026-11-03'
updated: '2026-11-03'
sourceUpdated: '2026-11-03T19:37:45.325Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-63198'
references:
  - url: 'https://github.com/traPtitech/traQ/security/advisories/GHSA-8cfq-jgf7-8m27'
    label: 'https://github.com/traPtitech/traQ/security/advisories/GHSA-8cfq-jgf7-8m27'
  - url: >-
      https://github.com/traPtitech/traQ/commit/5510fe8aa9bb15fc4755c78792381dbb03d576c3
    label: >-
      https://github.com/traPtitech/traQ/commit/5510fe8aa9bb15fc4755c78792381dbb03d576c3
  - url: 'https://github.com/traPtitech/traQ/releases/tag/v3.28.3'
    label: 'https://github.com/traPtitech/traQ/releases/tag/v3.28.3'
tags:
  - cve.org
epss: 0.00256
epssPercentile: 0.17253
ingestedAt: '2026-11-05T20:33:06.399Z'
---

## Overview

traQ is a messenger application built for Digital Creators Club traP. Prior to 3.28.3, OAuth2 silent authorization requests using prompt=none with an empty or omitted scope parameter check prior consent against the empty requested scope set even though all scopes registered for the client become eligible for issuance. An attacker who controls an OAuth client capable of receiving authorization codes can target a user who previously consented to only some client scopes and obtain an access token containing broader registered scopes without additional consent. A user who has never consented to the client still receives consent_required. This issue is fixed in version 3.28.3.

## Affected

- `traQ < 3.28.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.