CVE-2026-1629Network attack vector

Private channel disclosure via stale permalink previews

Published Mar 16, 2026 · Updated Mar 16, 2026

Information disclosure in Mattermost 10.11.0 through 10.11.10 allows remote authenticated users to read private channel content via permalink previews. The server retains cached permalink-preview data after channel access is revoked and serves that stale content without reapplying the current channel authorization. A user must first be able to access and preview the private-channel permalink; disclosure persists after removal until the cache resets or the user logs in again.

CVSS severity4.3
Medium
EPSS probability0.20%
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 10.11.0 through 10.11.10 allows remote authenticated users to read private channel content via permalink previews. The server retains cached permalink-preview data after channel access is revoked and serves that stale content without reapplying the current channel authorization. A user must first be able to access and preview the private-channel permalink; disclosure persists after removal until the cache resets or the user logs in again.

The record

CVE
CVE-2026-1629
Published
Mar 16, 2026
Updated
Mar 16, 2026
Vendor
Mattermost
Product
Mattermost
Classifications
CWE-672, T1213.005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 16, 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 <=10.11.10

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mattermost · Mattermostversion=10.11.0 <=10.11.10

Published CVSS scores

4.3Mattermost, Inc.CVSS:3.1/AV:N/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 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-672Operation on a Resource after Expiration or Release
T1213.005Messaging Applications

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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