CVE-2022-39203
Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.84%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
matrix-appservice-irc is an open source Node.js IRC bridge for Matrix. Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel. The vulnerability has been patched in matrix-appservice-irc 0.35.0. As a workaround operators may disable dynamic channel joining via `dynamicChannels.enabled` to prevent users from joining new channels, which prevents any new channels being bridged outside of what is already bridged, and what is specified in the config.
- 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
- 0.84% probability · 56th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-269
- Affected
- matrix/matrix irc bridge
- Source
- security-advisories@github.com
References
- https://github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-xvqg-mv25-rwvwMitigation, Third Party Advisory
- https://matrix.org/blog/2022/09/13/security-release-of-matrix-appservice-irc-0-35-0-high-severity/Vendor Advisory
- https://github.com/matrix-org/matrix-appservice-irc/security/advisories/GHSA-xvqg-mv25-rwvwMitigation, Third Party Advisory
- https://matrix.org/blog/2022/09/13/security-release-of-matrix-appservice-irc-0-35-0-high-severity/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.