---
id: CVE-2026-104480
title: >-
  Improper MLS Welcome roster validation in Discord libdave allows unauthorized
  group membership
summary: >-
  Discord libdave before 1.2.0 did not reject an MLS Welcome message when the
  resulting group roster contained an unrecognized participant. An attacker in
  control of the DAVE signaling path (the voice gateway, or an equivalent
  position abl…
severity: critical
cvss: 9.4
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N'
cvssSource: cna
cwe:
  - CWE-390
  - CWE-863
vendor: Discord
product: discord/libdave
affected:
  - discord/libdave >= 1.1.0 < 1.2.0
  - >-
    discord/libdave >= 7b15f1fc16f159da0478aa6be909e38f1e957833 <
    9686fbaea864aa19f0675e486672b6a77811b6a1
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T00:57:55.648Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-104480'
references:
  - url: >-
      https://github.com/discord/libdave/commit/9686fbaea864aa19f0675e486672b6a77811b6a1
    label: '[cpp] restore strict validation of MLS welcome state'
  - url: 'https://github.com/discord/libdave/releases/tag/v1.2.0/cpp'
    label: libdave v1.2.0 release notes
  - url: 'https://daveprotocol.com/'
    label: Discord Audio and Video End-to-End Encryption (DAVE) Protocol Whitepaper
  - url: 'https://github.com/discord/libdave'
tags:
  - cve.org
ingestedAt: '2026-10-02T02:07:09.203Z'
---

## Overview

Discord libdave before 1.2.0 did not reject an MLS Welcome message when the resulting group roster contained an unrecognized participant. An attacker in control of the DAVE signaling path (the voice gateway, or an equivalent position able to add, alter, or withhold signaling messages to a client) could cause affected clients to accept an unauthorized member into the end-to-end encrypted media session, compromising the confidentiality and integrity of audio and video.

## Affected

- `discord/libdave >= 1.1.0 < 1.2.0`
- `discord/libdave >= 7b15f1fc16f159da0478aa6be909e38f1e957833 < 9686fbaea864aa19f0675e486672b6a77811b6a1`

## Remediation

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