CVE-2024-1402Network attack vector

Server and mobile crashes via unbounded emoji reactions

Published Feb 9, 2024 · Updated Aug 1, 2024

Resource exhaustion in Mattermost allows remote authenticated users to crash the server by adding excessive emoji reactions to a post. SaveReactionForPost accepts custom emoji names without verifying that they exist and imposes no per-post limit on unique reactions, so post retrieval processes an attacker-expanded reaction set. Access to react to a post is required; retrieving the affected post overloads the server, and viewing it in the mobile app crashes that client.

CVSS severity4.3
Medium
EPSS probability0.52%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Mattermost allows remote authenticated users to crash the server by adding excessive emoji reactions to a post. SaveReactionForPost accepts custom emoji names without verifying that they exist and imposes no per-post limit on unique reactions, so post retrieval processes an attacker-expanded reaction set. Access to react to a post is required; retrieving the affected post overloads the server, and viewing it in the mobile app crashes that client.

The record

CVE
CVE-2024-1402
Published
Feb 9, 2024
Updated
Aug 1, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-400, T1499.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=8.1.7
  2. Affected versionversion=0 <=9.1.4
  3. Affected versionversion=0 <=9.2.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=8.1.7; version=0 <=9.1.4; version=0 <=9.2.3

Published CVSS scores

4.3Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.002Service Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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