Vulnerability Monitor

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CVE-2023-38691

matrix-appservice-bridge provides an API for setting up bridges. Starting in version 4.0.0 and prior to versions 8.1.2 and 9.0.1, a malicious Matrix server can use a foreign user's MXID in an OpenID exchange, allowing a bad actor to impersonate users when using the provisioning API. The library does not check that the servername part of the `sub` parameter (containing the user's *claimed* MXID) is the the same as the servername we are talking to. A malicious actor could spin up a server on any given domain, respond with a `sub` parameter according to the user they want to act as and use the resulting token to perform provisioning requests. Versions 8.1.2 and 9.0.1 contain a patch. As a workaround, disable the provisioning API.

Published

2023-08-04T17:15:11.063

Last Modified

2024-11-21T08:14:03.960

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 5.0 (MEDIUM)

Weaknesses

Type: Secondary
CWE-287
Type: Primary
CWE-287

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	matrix	matrix-appservice-bridge	< 8.1.2	Yes
Application	matrix	matrix-appservice-bridge	9.0.0	Yes

References

https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552 Patch ([email protected])
https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x Third Party Advisory ([email protected])
https://github.com/matrix-org/matrix-appservice-bridge/commit/4c6723a5e7beda65cdf1ae5dbb882e8beaac8552 Patch (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-vc7j-h8xg-fv5x Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)