What is CVE-2023-49809?

CVE-2023-49809 is a medium-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 4.3/10. Published 2023-12-12.

How severe is CVE-2023-49809?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Is CVE-2023-49809 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Resource exhaustion in Mattermost

CVE-2023-49809

Mattermost fails to handle a null request body in the /add endpoint, allowing a simple member to send a request with null request body to that endpoint and make it crash. After a few repetitions, the plugin is disabled.

Vulnerability class: DoS (Denial of Service)

Published 2023-12-12 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.006 (48.7th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 49th percentile — 48.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Mattermost — versions 0, 8.1.6, 9.2.0
Mattermost Server

Weakness classification (CWE)

CWE-400 — Uncontrolled Resource Consumption

Public proof-of-concept exploits

fkie-cad/nvd-json-data-feeds

References

mattermost.com/security-updates (Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2023-49809?: CVE-2023-49809 is a medium-severity vulnerability in Mattermost, classified under Uncontrolled Resource Consumption. CVSS score: 4.3/10. Published 2023-12-12.
How severe is CVE-2023-49809?: Medium severity. CVSS v3 base score is 4.3 out of 10.
Is CVE-2023-49809 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.