CVE-2022-39254 – When matrix-nio receives forwarded room keys, the receiver doesn't check if it requested the key from the forwarder

https://notcve.org/view.php?id=CVE-2022-39254

matrix-nio is a Python Matrix client library, designed according to sans I/O principles. Prior to version 0.20, when a users requests a room key from their devices, the software correctly remember the request. Once they receive a forwarded room key, they accept it without checking who the room key came from. This allows homeservers to try to insert room keys of questionable validity, potentially mounting an impersonation attack. Version 0.20 fixes the issue. matrix-nio es una librería cliente de Matrix en Python, diseñada según los principios de sans I/O. • https://github.com/poljar/matrix-nio/commit/b1cbf234a831daa160673defd596e6450e9c29f0 https://github.com/poljar/matrix-nio/security/advisories/GHSA-w4pr-4vjg-hffh • CWE-287: Improper Authentication CWE-322: Key Exchange without Entity Authentication •