Vulnerability · Published Aug 19, 2022 · Assigned by GitHub_M
CVE-2022-36009Incorrect parsing of access level in gomatrixserverlib and dendrite
Medium 5.0
In plain English
A medium-severity incorrect authorization in gomatrixserverlib from matrix-org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.9% (higher than 59% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/matrix-org/dendrite | 0.9.3 | GHSA-grvv-h2f9-7v9c |
| Go | github.com/matrix-org/gomatrixserverlib | 0.0.0-20220815091947-723fd495dde8 | GHSA-grvv-h2f9-7v9c |
| Go | github.com/matrix-org/gomatrixserverlib | 0.0.0-20220815091947-723fd495dde8 | GO-2022-0952 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| matrix-org | gomatrixserverlib | < 0.9.3 for dendrite < 723fd49 for gomatrixserverlib |
Weakness: CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L