Malicious remote can invite itself to an arbitrary local channel

Summary

Mattermost versions 9.9.x <= 9.9.0, 9.5.x <= 9.5.6, 9.7.x <= 9.7.5 and 9.8.x <= 9.8.1 fail to disallow unsolicited invites to expose access to local channels, when shared channels are enabled, which allows a malicious remote to send an invite with the ID of an existing local channel, and that local channel will then become shared without the consent of the local admin.

Timeline

1. Aug 1, 2024, 2:05 PM UTCCVE published
2. Aug 1, 2024, 2:33 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Aug 1, 2024, 4:07 PM UTCRecord last updated

Affected versions

• Mattermost Mattermost

  From 9.5.0 · through 9.5.6; From 9.7.0 · through 9.7.5; From 9.8.0 · through 9.8.1

• github.com/mattermost/mattermost-serverGo

  From 9.5.0+incompatible · fixed in 9.5.7+incompatible; From 9.7.0+incompatible · fixed in 9.7.6+incompatible; From 9.8.0+incompatible · fixed in 9.8.1+incompatible; From 9.9.0+incompatible · fixed in 9.9.1+incompatible

• github.com/mattermost/mattermost-server/v5Go

  All versions

• github.com/mattermost/mattermost-server/v6Go

  All versions

• github.com/mattermost/mattermost/server/v8Go

  All versions

• github.com/mattermost/mattermost/server/v8Go

  From 9.9.0 · fixed in 9.9.1

• github.com/mattermost/mattermost/server/v8Go

  From 9.5.0 · fixed in 9.5.7

• github.com/mattermost/mattermost/server/v8Go

  From 9.7.0 · fixed in 9.7.6

• github.com/mattermost/mattermost/server/v8Go

  From 9.8.0 · fixed in 9.8.1

References 1