GHSA-w4pr-4vjg-hffh
When matrix-nio receives forwarded room keys, the receiver doesn't check if it requested the key from the forwarder
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| PyPI | matrix-nio | < 0.20 | 0.20 |
Details
As written in the advisory (Markdown source, shown as plain text).
When matrix-nio before 0.20 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.
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References
External links from the advisory. They lead to third-party sites.