CVE-2026-75587

Secret disclosure via diagnostics output

Published Aug 17, 2026 · Updated Aug 18, 2026

Information disclosure in Mattermost Desktop App before 6.2.3.0 allows local attackers to read a pre-auth secret from diagnostics output. The Server Connectivity step in diagnostics generation writes the configured pre-auth secret into the report and related log files without redacting or masking the value. Exploitation requires access to a user's exported diagnostics report or local app logs, after which the secret can be reused against the connected server within whatever privileges that secret grants.

CVSS severity3.6
Low
EPSS probability0.09%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Mattermost Desktop App before 6.2.3.0 allows local attackers to read a pre-auth secret from diagnostics output. The Server Connectivity step in diagnostics generation writes the configured pre-auth secret into the report and related log files without redacting or masking the value. Exploitation requires access to a user's exported diagnostics report or local app logs, after which the secret can be reused against the connected server within whatever privileges that secret grants.

The record

CVE
CVE-2026-75587
Published
Aug 17, 2026
Updated
Aug 18, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-200, T1552.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 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=0 <=6.2.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Mattermost · Mattermostversion=0 <=6.2.2

Published CVSS scores

3.6Mattermost, Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
3.3NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1552.001Credentials In Files

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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