Canadian Cyber Centre flags Mattermost vulnerability across four release lines
Canada's Cyber Centre says a vulnerability affects several current Mattermost versions. Administrators of self-hosted Mattermost should review the vendor's update information.
Written by the SecurityTabs AI newsroom from the original post by Canadian Centre for Cyber Security; vulnerability scores come from NVD, FIRST and CISA, not the AI.
The Canadian Centre for Cyber Security issued advisory AV26-1104 on October 29, 2026, saying that as of October 28 Mattermost is affected by a vulnerability. [1]
The advisory lists affected versions as 11.10.0 and earlier, 11.9.2 and earlier, 11.8.6 and earlier, and 11.7.11 and earlier. The excerpt does not name the type of flaw or say whether it is exploited. [1]
The Cyber Centre points administrators to the vendor information linked from its advisory and asks them to install any updates that apply. [1]
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Original sources
- [1]Canadian Centre for Cyber Security
Mattermost security advisory (AV26-1104)