GHSA-grvv-h2f9-7v9c

gomatrixserverlib and Dendrite vulnerable to incorrect parsing of the event default power level in event auth

Source: GitHub Advisory Database (reviewed) Moderate CVE-2022-36009

Packages

Ecosystem	Package	Affected	Fixed in
Go	github.com/matrix-org/dendrite	< 0.9.3	0.9.3
Go	github.com/matrix-org/gomatrixserverlib	< 0.0.0-20220815091947-723fd495dde8	0.0.0-20220815091947-723fd495dde8

Details

As written in the advisory (Markdown source, shown as plain text).

### Impact 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. 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. ### Patches gomatrixserverlib contains a fix as of commit `723fd49` and Dendrite 0.9.3 has been updated accordingly. ### Workarounds Matrix rooms where the `"events_default"` power level has not been changed from the default of zero are not vulnerable. ### For more information If you have any questions or comments about this advisory, e-mail us at [[email protected]](mailto:[email protected]).

References

External links from the advisory. They lead to third-party sites.