CVE-2023-38691

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Summary

CVECVE-2023-38691
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2023-08-04 17:15:00 UTC
Updated2023-08-11 19:34:00 UTC
Descriptionmatrix-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.

Risk And Classification

Problem Types: CWE-287

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Matrix Matrix-appservice-bridge All All All All
Application Matrix Matrix-appservice-bridge 9.0.0 All All All

References

ReferenceSourceLinkTags
matrix-appservice-bridge doesn't verify the sub parameter of an openId token exchange, allowing unauthorized access to provisioning APIs · Advisory · matrix-org/matrix-appservice-bridge · GitHub MISC github.com
Merge pull request from GHSA-vc7j-h8xg-fv5x · matrix-org/matrix-appservice-bridge@4c6723a · GitHub MISC github.com
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