CVE-2026-11993
Received Received - Intake

Denial of Service in Mattermost via Excessive File Uploads

Publication date: 2026-09-14

Last updated on: 2026-09-14

Assigner: Mattermost, Inc.

Description
Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to properly enforce the limit of concurrent files being processed and handled failed files, which allows a user with permission to upload files to spawn more goroutines than intended and block the indexing of other files via uploading heavy files constantly to the server.. Mattermost Advisory ID: MMSA-2026-00696

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Meta Information

Published
2026-09-14
Last Modified
2026-09-14
Generated
2026-09-14
AI Q&A
2026-09-14
EPSS Evaluated
N/A
NVD
CVE-2026-11993
EUVD
EUVD-2026-77361

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
mattermost mattermost to 11.9.0 (inc)
mattermost mattermost to 11.8.4 (inc)
mattermost mattermost to 11.7.7 (inc)
mattermost mattermost to 10.11.22 (inc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-770 The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.

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Executive Summary

This vulnerability affects Mattermost versions 11.9.0 and below, 11.8.4 and below, 11.7.7 and below, and 10.11.22 and below. It allows users with file upload permissions to create excessive goroutines by constantly uploading large files, which blocks the server from indexing other files properly.

Impact Analysis

An attacker could exploit this to degrade server performance by consuming excessive resources, potentially causing denial-of-service conditions where legitimate users cannot upload or access files due to server overload.

Mitigation Strategies

Update Mattermost to a version that fixes the issue. Specifically, upgrade to versions beyond 11.9.0, 11.8.4, 11.7.7, or 10.11.22 depending on your current installation.

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