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🛡️ CVE-2025-27715 — mattermost

🟢 CVSS 3.3 — Low ✅ No Known Exploit NVD
3.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mattermost fail to prompt for explicit approval before adding a team admin to a private channel

Mattermost versions 9.11.x <= 9.11.8 fail to prompt for explicit approval before adding a team admin to a private channel, which team admins to joining private channels via crafted permalink links without explicit consent from them.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs administrative 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 low, availability none.

CVSS metrics in full

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

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: High — administrative rights are needed first.
  • 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: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: None.

Affected software

CVE-2025-27715 is recorded against 6 packages.

  • github.com/mattermost/mattermost-server
  • github.com/mattermost/mattermost-server/v5
  • github.com/mattermost/mattermost-server/v6
  • github.com/mattermost/mattermost/server/v8
  • mattermost
  • mattermost-server (from 9.11.0 up to 9.11.9)

Timeline and source

Published on 25 March 2025 and last revised on 3 March 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Advisory)
nvd.nist.gov (Advisory)
mattermost.com (Web)

Other advisories for this package

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

Details

Severity Low
CVSS Score 3.3
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:N
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-03-25
Updated 2026-08-20
Modified 2026-03-03
Fix URL N/A

Affected Packages

Software From version Fixed in
github.com/mattermost/mattermost-server — —
github.com/mattermost/mattermost-server/v5 — —
github.com/mattermost/mattermost-server/v6 — —
github.com/mattermost/mattermost/server/v8 — —
mattermost — —
mattermost-server 9.11.0 9.11.9

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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