CVE-2024-6428Network attack vector

User-management disruption via attacker-chosen user IDs

Published Jul 3, 2024 · Updated Aug 1, 2024

Improper access control in Mattermost allows remote attackers to disrupt user administration via crafted user-creation data. The new-user path accepts both RemoteId and an attacker-chosen user ID instead of rejecting that conflicting input, creating an account with the supplied ID. Reaching user creation is required, and the resulting malformed account can make administrative actions against that user fail without interrupting the broader service.

CVSS severity6.5
Medium
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in Mattermost allows remote attackers to disrupt user administration via crafted user-creation data. The new-user path accepts both RemoteId and an attacker-chosen user ID instead of rejecting that conflicting input, creating an account with the supplied ID. Reaching user creation is required, and the resulting malformed account can make administrative actions against that user fail without interrupting the broader service.

The record

CVE
CVE-2024-6428
Published
Jul 3, 2024
Updated
Aug 1, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-284
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 3, 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=9.5.0 <=9.5.5
  2. Affected versionversion=9.6.0 <=9.6.2
  3. Affected versionversion=9.7.0 <=9.7.4
  4. Affected versionversion=9.8.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mattermost · Mattermostversion=9.5.0 <=9.5.5; version=9.6.0 <=9.6.2; version=9.7.0 <=9.7.4; version=9.8.0

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-284Improper Access Control

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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