CVE-2022-36009
Description
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. Matrix rooms where the `"events_default"` power level has not been changed from the default of zero are not vulnerable. Users are advised to upgrade. There are no known workarounds for this issue.
How to fix
- github.com/matrix-org/dendrite0.9.3 or later
- github.com/matrix-org/gomatrixserverlib0.0.0-20220815091947-723fd495dde8 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| matrix dendrite | v ≤ 0.9.2 | — |
| matrix gomatrixserverlib | No range specified | — |
| github.com/matrix-org/dendriteGo | v < 0.9.3 | 0.9.3 |
| github.com/matrix-org/gomatrixserverlibGo | v < 0.0.0-20220815091947-723fd495dde8 | 0.0.0-20220815091947-723fd495dde8 |
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