CVE-2026-16251 — Mattermost local image proxy allows server memory exhaustion via unbounded image response buffering
Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to limit the size of remote image responses buffered in memory during local ima…
Published: 2026-10-16 · CVSS: 6.5 · CVSS 3.1
Mattermost versions 11.10.x <= 11.10.0, 11.7.x <= 11.7.9, 11.9.x <= 11.9.1, 11.8.x <= 11.8.5 fail to limit the size of remote image responses buffered in memory during local image proxy direct fetches, which allows a remote attacker to cause memory exhaustion on the server via a crafted oversized image response.. Mattermost Advisory ID: MMSA-2026-00726
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7