matrix-sdk-crypto contains potential impersonation via room key forward responses

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2022-39252: 0.63% estimated exploitation activity in the next 30 days; percentile 50.27 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact When matrix-rust-sdk before 0.6 requests a room key from our devices, it correctly accepts key forwards only if they are a response to a previous request. However, it doesn't check that the device that responded matches the device the key was requested from. This allows a malicious homeserver to insert room keys of questionable validity into the key store in some situations, potentially assisting in an impersonation attack. Note that even if key injection succeeds in this way, all forwarded keys have the imported flag set, which is used as an indicator that such keys have lesser authentication properties (and should be marked as such in clients, e.g. with a grey shield besides the message). For more information If you have any questions or comments about this advisory, e-mail us at security@matrix.org.

Published by the source

30 Sep 2022, 22:51 UTC

Last modified by the source

3 Apr 2023, 19:28 UTC

Source last checked

26 Oct 2026, 15:33 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vp68-2wrm-69qm

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# Patch Next advisory brief: CVE-2022-39252

Advisory: matrix-sdk-crypto contains potential impersonation via room key forward responses
IDs: CVE-2022-39252, GHSA-vp68-2wrm-69qm
Record: https://patchnext.com/advisories/cve-2022-39252 (revision 1, source checked 26 Oct 2026, 15:33 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: matrix-sdk-crypto 0.6.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io matrix-sdk-crypto: affected < 0.6.0; fixed in 0.6.0

## Suggested inspection (read-only)
- crates.io matrix-sdk-crypto: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on matrix-sdk-crypto.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-vp68-2wrm-69qm (GitHub-reviewed advisory GHSA-vp68-2wrm-69qm lists affected ranges: crates.io matrix-sdk-crypto >=0 <0.6.0)

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