CVE-2023-4478Network attack vector

Account access denial via signup parameter tampering

Published Aug 25, 2023 · Updated Sep 30, 2024

Parameter tampering in Mattermost 7.8.8 and earlier, 7.9.0 through 7.10.4, and 8.0.0 allows remote attackers to block later account access. The signup user-creation path accepts account-state values from the request without restricting which parameters the client can set, allowing an account to be stored as inactive. Email-based account creation must be enabled, and the attacker must register the intended email first; the resulting account remains unusable until an administrator activates it.

CVSS severity4.3
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Parameter tampering in Mattermost 7.8.8 and earlier, 7.9.0 through 7.10.4, and 8.0.0 allows remote attackers to block later account access. The signup user-creation path accepts account-state values from the request without restricting which parameters the client can set, allowing an account to be stored as inactive. Email-based account creation must be enabled, and the attacker must register the intended email first; the resulting account remains unusable until an administrator activates it.

The record

CVE
CVE-2023-4478
Published
Aug 25, 2023
Updated
Sep 30, 2024
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-74, T1531
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 30, 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 <=7.10.4
  2. Affected versionversion=0 <=7.8.8
  3. Affected versionversion=8.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=7.10.4; version=0 <=7.8.8; version=8.0.0

Published CVSS scores

4.3Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
8.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1531Account Access Removal

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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