---
cve: "CVE-2026-84894"
severity: "HIGH"
cvss: 7.5
epss: "0.2%"
vendor: "Meta Platforms, Inc"
kev: false
exploited: false
published: "2026-09-28 19:16:50"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-10-08T11:47:35+02:00"
---

# CVE-2026-84894

> 7.5 HIGH · 🧪 PoC

## Beschreibung

In moxygen before commit 004123dd24c3, MoQSession::dataStreamReadLoop keeps using a stream read handle after reading a FIN, which invalidates the handle under proxygen's WebTransport API. A remote peer can trigger the stale use by opening a data stream that names an unknown track alias and carries the FIN in the same write.

## CNA-Record (Kanon, cvelistV5)

- CNA: **Meta**
- State: PUBLISHED
- Stand: 2026-09-30 15:05:50

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **yes**
  - Technical Impact: **partial**

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Keine | good |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 004123dd24c30dad6b649163575145f240dabc94 (Commit)

## Referenzen

- <https://www.facebook.com/security/advisories/cve-2026-84894>
- <https://github.com/facebookexperimental/moxygen/commit/004123dd24c30dad6b649163575145f240dabc94>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2026-84894/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_