CVE-2022-36009
Matrix rooms where the `"events_default"` power level has not been changed from the default of zero are not vulnerable.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.82%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.82% probability · 55th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-863
- Affected
- matrix/dendrite · matrix/gomatrixserverlib
- Source
- security-advisories@github.com
References
- https://github.com/matrix-org/gomatrixserverlib/commit/723fd495dde835d078b9f2074b6b62c06dea4575Patch, Third Party Advisory
- https://github.com/matrix-org/gomatrixserverlib/security/advisories/GHSA-grvv-h2f9-7v9cThird Party Advisory
- https://matrix.org/docs/guides/moderation/#power-levelsVendor Advisory
- https://github.com/matrix-org/gomatrixserverlib/commit/723fd495dde835d078b9f2074b6b62c06dea4575Patch, Third Party Advisory
- https://github.com/matrix-org/gomatrixserverlib/security/advisories/GHSA-grvv-h2f9-7v9cThird Party Advisory
- https://matrix.org/docs/guides/moderation/#power-levelsVendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.