CVE-2022-39200 – Signature checks not applied to some retrieved missing events
https://notcve.org/view.php?id=CVE-2022-39200
Dendrite is a Matrix homeserver written in Go. In affected versions events retrieved from a remote homeserver using the `/get_missing_events` path did not have their signatures verified correctly. This could potentially allow a remote homeserver to provide invalid/modified events to Dendrite via this endpoint. Note that this does not apply to events retrieved through other endpoints (e.g. `/event`, `/state`) as they have been correctly verified. • https://github.com/matrix-org/dendrite/commit/2792d0490f3771488bad346981b8c26479a872c3 https://github.com/matrix-org/dendrite/security/advisories/GHSA-pfw4-xjgm-267c • CWE-347: Improper Verification of Cryptographic Signature •
CVE-2022-36009 – Incorrect parsing of access level in gomatrixserverlib and dendrite
https://notcve.org/view.php?id=CVE-2022-36009
gomatrixserverlib is a Go library for matrix protocol federation. Dendrite is a Matrix homeserver written in Go, an alternative to Synapse. The power level parsing within gomatrixserverlib was failing to parse the `"events_default"` key of the `m.room.power_levels` event, defaulting the event default power level to zero in all cases. Power levels are the matrix terminology for user access level. In rooms where the `"events_default"` power level had been changed, this could result in events either being incorrectly authorised or rejected by Dendrite servers. gomatrixserverlib contains a fix as of commit `723fd49` and Dendrite 0.9.3 has been updated accordingly. • https://github.com/matrix-org/gomatrixserverlib/commit/723fd495dde835d078b9f2074b6b62c06dea4575 https://github.com/matrix-org/gomatrixserverlib/security/advisories/GHSA-grvv-h2f9-7v9c https://matrix.org/docs/guides/moderation/#power-levels • CWE-863: Incorrect Authorization •