Is CVE-2026-5308 actively exploited?

No active exploitation of CVE-2026-5308 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-5308 be exploited remotely?

Yes. CVE-2026-5308 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-5308?

CVE-2026-5308 has a CVSS score of 7.5 (HIGH).

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HIGH

CVE-2026-5308

CWE-400Published: May 22, 2026· Updated: May 22, 2026

7.5

CVSS v3.1

EPSS:0.04%probability of exploitation in 30 daysPercentile:11.0th

Official Description

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to enforce request body size limits on plugin HTTP endpoints which allows an attacker to cause a denial of service via crafted oversized HTTP requests.. Mattermost Advisory ID: MMSA-2026-00646

NVD Source

Technical Analysis

CVE-2026-5308 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.