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CVE-2026-4286

LOW 3.1

Published 2026-05-18 · Last modified 2026-05-18

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to check if {{team_id}} was being changed when updating playbooks, allowing users with only {{Manage Playbook Configurations}} permission to change a playbook's team, bypassing manage members restriction via PUT api. Mattermost Advisory ID: MMSA-2025-00552

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.1%chance of exploitation in 30 days · 4th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

3.1CVSS 3.1 · LOW

  • ConfidentialityNone
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • Access: Reachable over the network — no local access needed
  • Privileges: Requires a low-privilege account
  • User interaction: No user interaction needed
  • Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Affected

Vendors Mattermost

Products Mattermost

Weakness (CWE)

  • CWE-863: Incorrect authorization

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N

References

Advisories

Sources: NVD · CVE.org · EPSS