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Go/github.com/mattermost/mattermost-server CVE-2026-4054: medium 4.3, EPSS 0.24%

Mattermost doesn't validate the response body of proxied images

Action: Upgrade github.com/mattermost/mattermost-server to 0.0.0-20260414103857-b21ef302025e or later.

go get github.com/mattermost/mattermost-server@v11.5.2
go get github.com/mattermost/mattermost-server@v0.0.0-20260414103857-b21ef302025e
go get github.com/mattermost/mattermost-server@v11.4.4

Affected

introducedfixedlast affected
11.5.011.5.2-
0.0.0-20250731163400-5b955468ea1e0.0.0-20260414103857-b21ef302025e-
11.4.011.4.4-

Fixed versions

11.5.20.0.0-20260414103857-b21ef302025e11.4.4

Sources

CVE-2026-4054 · published · modified · JSON