What is CVE-2022-39246?

CVE-2022-39246 is a high-severity vulnerability in Matrix Software Development Kit, classified under Improper Authentication. CVSS score: 7.5/10. Published 2022-09-28.

How severe is CVE-2022-39246?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2022-39246 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Matrix Software Development Kit

CVE-2022-39246

matrix-android-sdk2 is the Matrix SDK for Android. Prior to version 1.5.1, 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 key forwarding strategy implemented in the matrix-android-sdk2 that is too permissive. Starting with version 1.5.1, the default policy for accepting key forwards has been made more strict in the matrix-android-sdk2. The matrix-android-sdk2 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). As a workaroubnd, current users of the SDK can disable key forwarding in their forks using `CryptoService#enableKeyGossiping(enable: Boolean)`.

Vulnerability class: Broken Authentication

Published 2022-09-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.008 (56.4th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.008 · change: +0.002

Affected products

Matrix Software Development Kit
Matrix-Org Matrix-Android-Sdk2 — versions < 1.5.1

Weakness classification (CWE)

Public proof-of-concept exploits

karimhabush/cyberowl

References

github.com/matrix-org/matrix-spec-proposals/pull/3061 (Patch, Third Party Advisory)
github.com/matrix-org/matrix-android-sdk2/security/advisories/GHSA-2pvj-p485-cp… (Patch, Third Party Advisory, Mitigation)
github.com/matrix-org/matrix-android-sdk2/commit/77df720a238d17308deab83ecaa37f… (Patch, Third Party Advisory)
github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.5.1 (Third Party Advisory, Release Notes)

Frequently asked questions

What is CVE-2022-39246?: CVE-2022-39246 is a high-severity vulnerability in Matrix Software Development Kit, classified under Improper Authentication. CVSS score: 7.5/10. Published 2022-09-28.
How severe is CVE-2022-39246?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2022-39246 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.