CVE-2026-6340
Memory Exhaustion via Malicious 7zip File Upload
CVSS Score
4.3
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 fail to validate 7zip archive structure before processing which allows an authenticated attacker to cause server memory exhaustion and denial of service via uploading a specially crafted 7zip file with excessive folder declarations.. Mattermost Advisory ID: MMSA-2026-00573
| CWE | CWE-789 |
| Vendor | mattermost |
| Product | mattermost |
| Published | May 18, 2026 |
Stay Ahead of the Next One
Get instant alerts for mattermost mattermost
Be the first to know when new medium vulnerabilities affecting mattermost mattermost are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Affected Versions
Mattermost / Mattermost
11.5.0 ≤ 11.5.1 10.11.0 ≤ 10.11.13 11.4.0 ≤ 11.4.3
Credits
Juho Forsén