CVE-2026-27769Network attack vector

Status manipulation via unchecked workspace ownership

Published Apr 15, 2026 · Updated Apr 15, 2026

Missing authorization in Mattermost 10.11.0 through 10.11.12 allows remote attackers on a connected server to alter local users' displayed status. The Connected Workspaces API applies a status update without verifying that the referenced user belongs to the workspace originating the request. Exploitation requires enabled Connected Workspaces and a trusted connection established by system administrators; the reported effect is limited to displayed presence status.

CVSS severity2.7
Low
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in Mattermost 10.11.0 through 10.11.12 allows remote attackers on a connected server to alter local users' displayed status. The Connected Workspaces API applies a status update without verifying that the referenced user belongs to the workspace originating the request. Exploitation requires enabled Connected Workspaces and a trusted connection established by system administrators; the reported effect is limited to displayed presence status.

The record

CVE
CVE-2026-27769
Published
Apr 15, 2026
Updated
Apr 15, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-862, T1565.001
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Apr 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2026Record 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=10.11.0 <=10.11.12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.12

Published CVSS scores

2.7Mattermost, Inc.CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:N

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1565.001Stored Data Manipulation

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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