High · published October 16, 2025
⚡ Any attacker can crash the party and join any Mattermost team they want, all thanks to a sneaky little flaw! 🎉 Think of it like a VIP event where anyone can use a forged invitation to waltz in without anyone checking their credentials. This vulnerability lets anyone manipulate their way into any Mattermost team, bypassing all the bouncers! An attacker could use this flaw to gain unauthorized access to sensitive conversations and files, potentially compromising your team's integrity. Imagine having a stranger in the room, listening in on private discussions and even mingling with your most confidential projects—absolutely devastating!
Think of it like a VIP event where anyone can use a forged invitation to waltz in without anyone checking their credentials. This vulnerability lets anyone manipulate their way into any Mattermost team, bypassing all the bouncers! This vulnerability stems from Mattermost's failure to verify a user’s permissions when joining teams via an original invite token, allowing manipulation of the RelayState parameter to bypass restrictions.
An attacker could use this flaw to gain unauthorized access to sensitive conversations and files, potentially compromising your team's integrity. Imagine having a stranger in the room, listening in on private discussions and even mingling with your most confidential projects—absolutely devastating! Update Mattermost to versions 10.11.2, 10.10.3, or 10.5.11 to patch this vulnerability immediately. It’s crucial to review team permissions and audit any recent access logs to identify unauthorized entries. Don't leave your server's door wide open! You've got this! Fix this vulnerability and secure your Mattermost environment like a pro! 🛡️
| Product | Versions | Fixed in |
|---|---|---|
| mattermost/mattermost_server | ≥ 10.5.0, < 10.5.11 | 10.5.11 |
| mattermost/mattermost_server | ≥ 10.10.0, < 10.10.3 | 10.10.3 |
| mattermost/mattermost_server | ≥ 10.11.0, < 10.11.3 | 10.11.3 |