CVE-2026-15814 — Uploading a crafted image causes excessive memory allocation in the Mattermost Server

Description (CNA)

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 limit the amount of memory allocated when decoding uploaded image files which allows an authenticated user to cause excessive server memory consumption and potential denial of service via uploading a specially crafted image as a profile picture, channel file attachment, team icon, or custom brand image. Mattermost Advisory ID: MMSA-2026-00719

Affected (CNA)

Vendor / product	Versions
Mattermost / Mattermost	affected 11.9.0 through 11.9.0; affected 11.8.0 through 11.8.4; affected 11.7.0 through 11.7.7; affected 10.11.0 through 10.11.22; unaffected 11.10.0; unaffected 11.9.1; unaffected 11.8.5; unaffected 11.7.8; unaffected 10.11.23

CWE

CWE-409

References

https://mattermost.com/security-updates

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.