# CVE-2026-104480: Improper MLS Welcome roster validation in Discord libdave allows unauthorized group membership

> An attacker controlling the signaling path can inject unauthorized members into encrypted Discord media sessions, compromising audio and video confidentiality and integrity.

- **Severity:** Critical 9.4 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Oct 2026
- **Updated:** 2 Oct 2026
- **Also known as:** GHSA-3q99-x36r-rchh

## What is CVE-2026-104480?

CVE-2026-104480 is a critical missing authorization vulnerability in Discord libdave, published on 2 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-863 (Incorrect Authorization), CWE-390 (Detection of Error Condition Without Action)

## Which versions are affected by CVE-2026-104480?


## How do I fix CVE-2026-104480?

No fix has been published for CVE-2026-104480 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-104480 being exploited?

There is no known exploitation of CVE-2026-104480 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-104480 and fix it if it is affected.

What it is: CVE-2026-104480 is a critical missing authorization vulnerability in Discord libdave, published on 2 Oct 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-2026-104480 in the wild and no public exploit code.

Affected product: Discord libdave. 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-2026-104480/ (Markdown: https://insights.sbomify.com/CVE-2026-104480/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-104480
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-104480
- OSV: https://osv.dev/vulnerability/CVE-2026-104480

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-104480/
Summaries are generated and may contain mistakes; the official description above is the record.