Incorrect parsing of access level in gomatrixserverlib and dendrite
CVE-2022-36009

5MEDIUM

Key Information:

Vendor

Matrix-org

Status
Gomatrixserverlib
Vendor
CVE Published:
19 August 2022

What is 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. 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.

Affected Version(s)

gomatrixserverlib < 0.9.3 for dendrite < 0.9.3 for dendrite

gomatrixserverlib < 723fd49 for gomatrixserverlib < 723fd49 for gomatrixserverlib

References

https://github.com/matrix-org/gomatrixserverlib/security/...
x_refsource_CONFIRM
https://github.com/matrix-org/gomatrixserverlib/commit/72...
x_refsource_MISC
https://matrix.org/docs/guides/moderation/#power-levels
x_refsource_MISC

CVSS V3.1

Score:
5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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