CVE-2025-14822: DoS from quadratic complexity in model.ParseHashtags

Published Jan 16, 2026
·
Updated

Mattermost versions 10.11.x <= 10.11.8 fail to validate input size before processing hashtags which allows an authenticated attacker to exhaust CPU resources via a single HTTP request containing a post with thousands space-separated tokens

Affected Software

4 affected componentsFixes available
Mattermost Mattermost<=10.11.8
Mattermost Mattermost Server>=10.11.0<10.11.9
go/github.com/mattermost/mattermost-server>=11.0.0<11.2.0
11.2.0
go/github.com/mattermost/mattermost-server>=10.11.0<=10.11.8
10.11.9

Remediation

Information

Update Mattermost to versions 11.2.0, 10.11.9 or higher.

Event History

Jan 16, 2026
CVE Published
via MITRE·08:52 AM
Data Sourced
via MITRE·08:52 AM
RemedyDescriptionSeverityWeakness
Data Sourced
via NVD·09:16 AM
DescriptionSeverityWeaknessAffected Software
Advisory Published
via GitHub·09:31 AM
Data Sourced
via GitHub·09:31 AM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2025-14822?

CVE-2025-14822 is a high severity vulnerability due to its potential for Denial of Service (DoS) attacks.

2

How do I fix CVE-2025-14822?

To mitigate CVE-2025-14822, upgrade Mattermost to version 10.11.9 or later where the vulnerability is patched.

3

Who is affected by CVE-2025-14822?

CVE-2025-14822 affects Mattermost versions 10.11.x up to and including 10.11.8.

4

What type of attack does CVE-2025-14822 allow?

CVE-2025-14822 allows authenticated attackers to exhaust server CPU resources by sending specially crafted HTTP requests.

5

What is the impact of CVE-2025-14822?

The impact of CVE-2025-14822 is a potential Denial of Service, leading to degraded performance or unavailability of the Mattermost service.

Contact

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