Is CVE-2026-2456 actively exploited?

CVE-2026-2456 has no public evidence of in-the-wild exploitation as of 2026-03-18.

What is the CVSS score for CVE-2026-2456?

CVE-2026-2456 has a CVSS score of 5.3 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H.

How do I patch CVE-2026-2456?

Patch guidance is available from mattermost security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-2456.

CVE-2026-2456 - remediation guidance & executive summary

Q: Which products are affected by CVE-2026-2456?

3 products: mattermost mattermost server, mattermost mattermost server, mattermost mattermost server.

Description

Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 Mattermost fails to limit the size of responses from integration action endpoints, which allows an authenticated attacker to cause server memory exhaustion and denial of service via a malicious integration server that returns an arbitrarily large response when a user clicks an interactive message button.. Mattermost Advisory ID: MMSA-2026-00571

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack Vector: network
Complexity: high
Privileges: none
User Action: required
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
Weaknesses: CWE-789

Metadata

Primary Vendor: MATTERMOST
Published: 3/16/2026
Last Modified: 3/18/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

mattermost : mattermost_servermattermost : mattermost_servermattermost : mattermost_server

Remediation Guidance

Executive Summary

Cite this page

CVE-2026-2456. CVEDatabase.com. Retrieved 1 May 2026. https://cvedatabase.com/cve/CVE-2026-2456

View on NIST NVD

CVE-2026-2456 vulnerability