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CVE-2026-16251

CVE-2026-16251 · Mattermost local image proxy allows server memory exhaustion via unbounded image response buffering

This page contains facts from public vulnerability sources. Check the original advisory before updating.

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

CVSS 6.5 · Medium · EPSS 0.3%

Published
Updated

Affected products and versions

  • mattermost

    Versions
    • ≥ 11.10.0, ≤ 11.10.0: Affected (semver)
    • ≥ 11.7.0, ≤ 11.7.9: Affected (semver)
    • ≥ 11.9.0, ≤ 11.9.1: Affected (semver)
    • ≥ 11.8.0, ≤ 11.8.5: Affected (semver)
    • 11.11.0: Not affected
    • 11.10.1: Not affected
    • 11.7.10: Not affected
    • 11.9.2: Not affected
    • 11.8.6: Not affected

    No fix published

Original sources

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