Loading vulnerability…
CVE-2026-9816 is an improper authorization vulnerability in Mattermost BoardMember.Scheme* field handling. Affected Mattermost releases do not validate these fields server-side in board-member insertion and team archive-import processing. A board editor or non-guest team member can exploit the flaw to assign board administrator privileges to arbitrary users. Affected versions are 10.11.0 through 10.11.21, 11.7.0 through 11.7.6, and 11.8.0 through 11.8.3.
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
If you can’t patch tonight, do this now.
Patch, then assume compromise.
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
12 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A specific Mattermost Server vulnerability referenced by this Nessus plugin/advisory entry; it is the source for the listed CVSS score, but no technical flaw details are provided in the content.
A specific vulnerability affecting Mattermost versions prior to or equal to 10.11.21, 11.7.6, and 11.8.3.
A specific vulnerability affecting Mattermost versions prior to or equal to 10.11.21, 11.7.6, and 11.8.3.
An improper authorization vulnerability in Mattermost that fails to validate BoardMember.Scheme* fields server-side, allowing a board editor or non-guest team member to grant board admin privileges to arbitrary users.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.