CVE-2026-5755
Denial of service via crafted TIFF file upload
CVSS Score
6.5
EPSS Score
0.0%
EPSS Percentile
0th
Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.2, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service (server OOM) via uploading a crafted TIFF file or posting a URL that serves one.. Mattermost Advisory ID: MMSA-2026-00648
| CWE | CWE-400 |
| Vendor | mattermost |
| Product | mattermost |
| Published | May 22, 2026 |
| Last Updated | May 22, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
Mattermost / Mattermost
11.6.0 ≤ 11.6.0 11.5.0 ≤ 11.5.2 11.5.0 ≤ 11.5.3 11.4.0 ≤ 11.4.4 10.11.0 ≤ 10.11.14
Credits
ZephrFish