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Incorrect parsing of the event default power level in event auth

Moderate
neilalexander published GHSA-grvv-h2f9-7v9c Aug 15, 2022

Package

gomod dendrite (Go)

Affected versions

<= 0.9.2

Patched versions

0.9.3
gomod gomatrixserverlib (Go)
<= 6a49c18
723fd49

Description

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].

Severity

Moderate

CVE ID

CVE-2022-36009

Weaknesses

No CWEs