Low severity3.7NVD Advisory· Published Apr 9, 2026· Updated Apr 25, 2026

CVE-2026-21388

Description

Mattermost Plugins versions <=2.3.1 fail to limit the request body size on the {{/lifecycle}} webhook endpoint which allows an authenticated attacker to cause memory exhaustion and denial of service via sending an oversized JSON payload. Mattermost Advisory ID: MMSA-2026-00610

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

Package	Affected versions	Patched versions
github.com/mattermost/mattermost-plugin-msteamsGo	< 1.15.1-0.20260213190728-6fe4d295592e	1.15.1-0.20260213190728-6fe4d295592e

Affected products

Mattermost/Mattermost
cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*
Range: <=2.3.1
ghsa-coords
pkg:golang/github.com/mattermost/mattermost-plugin-msteams
Range: < 1.15.1-0.20260213190728-6fe4d295592e

Patches

Vulnerability mechanics

References

github.com/advisories/GHSA-x274-8qfc-hrgfghsaADVISORY
mattermost.com/security-updatesnvdVendor AdvisoryWEB
nvd.nist.gov/vuln/detail/CVE-2026-21388ghsaADVISORY
github.com/mattermost/mattermost-plugin-msteams/commit/6fe4d295592ecc8767d67e69286cbeec01be3210ghsaWEB
github.com/mattermost/mattermost-plugin-msteams/releases/tag/v2.3.2ghsaWEB

News mentions

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cvss	0.240
epss	0.000
exploit	0.000
kev	0.000
patch	-0.070
ransomware	0.000