---
cve: "CVE-2022-39257"
severity: "HIGH"
cvss: 7.5
epss: "78%"
vendor: "matrix-org"
kev: false
exploited: false
published: "2022-09-28 21:15:14"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-10T17:28:40+02:00"
---

# CVE-2022-39257

> 7.5 HIGH · 🧪 PoC

## Beschreibung

Matrix iOS SDK allows developers to build iOS apps compatible with Matrix. Prior to version 0.23.19, an attacker cooperating with a malicious homeserver can construct messages appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the matrix-ios-sdk implementing a too permissive key forwarding strategy. The default policy for accepting key forwards has been made more strict in the matrix-ios-sdk version 0.23.19. matrix-ios-sdk will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately (for example, by showing a warning for such messages). This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 | Keine | good |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Keine | good |

## Patch verfügbar (OSV)

- 4442142c7111cf051d30d9015de7266a515bfc95 (Commit)
- 5ca86c328a5faaab429c240551cb9ca8f0f6262c (Commit)

## Referenzen

- <https://matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sdks-and-clients>
- <https://github.com/matrix-org/matrix-ios-sdk/commit/5ca86c328a5faaab429c240551cb9ca8f0f6262c>
- <https://github.com/matrix-org/matrix-ios-sdk/releases/tag/v0.23.19>
- <https://github.com/matrix-org/matrix-ios-sdk/security/advisories/GHSA-qxr3-5jmq-xcf4>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2022-39257) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_