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🛡️ CVE-2026-9824 — mattermost-server

🟡 CVSS 4.3 — Medium ✅ No Known Exploit CWE-862 NVD
4.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to check the manage_shared_channels permission in the /share-channel autocomplete handler, which allows an authenticated user without that permission to enumerate configured remote cluster connection metadata via slash command autocomplete.. Mattermost Advisory ID: MMSA-2026-00676

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: Low — limited, and the attacker does not choose what is affected.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

CVE-2026-9824 is classified as CWE-862: Missing Authorization. No authorisation check is performed before carrying out a restricted action.

Affected software

CVE-2026-9824 is recorded against 1 package.

  • mattermost-server (from 11.7.0 up to 11.7.3)

Timeline and source

Published on 13 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

mattermost.com

Other advisories for this package

mattermost-server has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-862: Missing Authorization) in other software:

Details

Severity MEDIUM
CVSS Score 4.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CWE CWE-862
Public Exploit ✅ No
Source NVD
Published 2026-07-13
Updated 2026-08-20
Modified 2026-07-13
Fix URL N/A

Affected Packages

Software From version Fixed in
mattermost-server 11.7.0 11.7.3

References

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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