CVE-2024-47003: DoS via non-string message using permalink embed

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-09-26 · updated 2026-06-17
Weakness: CWE-400

Description

Mattermost versions 9.11.x <= 9.11.0 and 9.5.x <= 9.5.8 fail to validate that the message of the permalink post is a string, which allows an attacker to send a non-string value as the message of a permalink post and crash the frontend.

Affected products

Mattermost: from 9.5.0 before 9.5.9; 9.11.0, 9.11.0-rc1, 9.11.0-rc2, 9.11.0-rc3 — fixed in 9.5.9

How to fix

Upgrade to a fixed version: Mattermost 9.5.9. Check the vendor advisory for mitigations.

References

https://mattermost.com/security-updates

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