CVE-2026-2456 — Vulnetix

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CVE-2026-2456 PUBLISHED CVSS 5.300000190734863 MEDIUM

Mattermost fails to limit the size of responses from integration action endpoints

EPSS 0.04% · 10.6th percentile

Risk Scores

CVSS v3.1

5.300000190734863

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Score

0.04%

10.6th percentile

Affected Products

Vendor	Product	Versions
github.com	mattermost/mattermost-server	10.11.0-rc1, 0, 11.3.0-rc1
Mattermost	Mattermost	11.3.0, 11.2.0, 10.11.0
mattermost	mattermost_server	10.11.0, 11.2.0, 10.11.0
github.com	mattermost/mattermost/server/v8	0, 0, 0

Timeline

Feb 16, 2026 CVE Published
Feb 16, 2026 PoC Published
Mar 16, 2026 EPSS Score
Mar 17, 2026 CVE Updated
Mar 17, 2026 EPSS Score
Mar 18, 2026 EPSS Score
Mar 18, 2026 PoC Published
Mar 19, 2026 EPSS Score
Mar 20, 2026 EPSS Score
Mar 21, 2026 EPSS Score
Mar 22, 2026 EPSS Score
Mar 22, 2026 Coalition ESS Score

References

MMSA-2026-00571 vendor-advisory
https://mattermost.com/security-updates/ advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-2456 advisory
https://github.com/mattermost/mattermost/commit/fe3052073dc67e3c920baf9fe7efd44ac1d8124c url
https://github.com/mattermost/mattermost package

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