CVE-2024-41926: Mattermost allows remote actor to set arbitrary RemoteId values for synced users

August 1, 2024 (updated July 9, 2025)

Mattermost versions 9.9.x <= 9.9.0 and 9.5.x <= 9.5.6 fail to validate the source of sync messages and only allow the correct remote IDs, which allows a malicious remote to set arbitrary RemoteId values for synced users and therefore claim that a user was synced from another remote.

References

github.com/advisories/GHSA-9fpw-c9x7-cv3j
github.com/mattermost/mattermost
github.com/mattermost/mattermost/commit/5114c3b7cdb84086959bf0ef8bc5afdaedf9fef6
mattermost.com/security-updates
nvd.nist.gov/vuln/detail/CVE-2024-41926
pkg.go.dev/vuln/GO-2024-3022

Code Behaviors & Features

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