CVE-2026-2456

EUVD-2026-12383
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
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
5.3 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
MattermostCNA
5.3 MEDIUM
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Affected Products (NVD)
VendorProductVersion
mattermostmattermost
11.3.0 ≤
𝑥
≤ 11.3.0
mattermostmattermost
11.2.0 ≤
𝑥
≤ 11.2.2
mattermostmattermost
10.11.0 ≤
𝑥
≤ 10.11.10
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://mattermost.com/security-updates