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MEDIUM4.3

GHSA-32h7-7j94-8fc2

Mattermost vulnerable to denial of service via large number of emoji reactions

Quick fix

GHSA-32h7-7j94-8fc2 — github.com/mattermost/mattermost/server/v8: upgrade to the fixed version with the command below.

go get github.com/mattermost/mattermost/server/v8@v8.1.8

Details

Mattermost fails to check if a custom emoji reaction exists when sending it to a post and to limit the amount of custom emojis allowed to be added in a post, allowing an attacker sending a huge amount of non-existent custom emojis in a post to crash the mobile app of a user seeing the post. Fetching posts with huge amounts of reactions results in Uncontrolled Resource Consumption.

Are you affected?

Enter the version of the package you're using.

Affected packages

Go/github.com/mattermost/mattermost/server/v8
Introduced in: 0Fixed in: 8.1.8
Fixgo get github.com/mattermost/mattermost/server/v8@v8.1.8
Go/github.com/mattermost/mattermost/server/v8
Introduced in: 9.2.0Fixed in: 9.2.4
Fixgo get github.com/mattermost/mattermost/server/v8@v9.2.4
Go/github.com/mattermost/mattermost/server/v8
Introduced in: 9.1.0Fixed in: 9.1.5
Fixgo get github.com/mattermost/mattermost/server/v8@v9.1.5

References