Mattermost 10.11.x <=10.11.8: HASHTAG Size Check Flaw Exposes CPU Exhaustion
CVE-2025-14822 Published on January 16, 2026
DoS from quadratic complexity in model.ParseHashtags
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
Vulnerability Analysis
CVE-2025-14822 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.
Weakness Type
Inefficient Algorithmic Complexity
An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.
Products Associated with CVE-2025-14822
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Affected Versions
Mattermost:- Version 10.11.0, <= 10.11.8 is affected.
- Version 11.2.0 is unaffected.
- Version 10.11.9 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.