CVE-2026-3636 PUBLISHED

Sanitize team member data returned by API

Assigner: Mattermost
Reserved: 06.03.2026 Published: 22.05.2026 Updated: 22.05.2026

Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to sanitize team member data when returned via API to users without elevated permissions which allows a user without permissions to get data about team members roles via invoking various team API endpoints.. Mattermost Advisory ID: MMSA-2026-00626

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
CVSS Score: 4.3

Product Status

Vendor Mattermost
Product Mattermost
Versions Default: unaffected
  • affected from 11.6.0 to 11.6.0 (incl.)
  • affected from 11.5.0 to 11.5.3 (incl.)
  • affected from 11.4.0 to 11.4.4 (incl.)
  • affected from 10.11.0 to 10.11.14 (incl.)
  • Version 11.7.0 is unaffected
  • Version 11.6.1 is unaffected
  • Version 11.5.4 is unaffected
  • Version 11.4.5 is unaffected
  • Version 10.11.15 is unaffected

Solutions

Update Mattermost to versions 11.7.0, 11.6.1, 11.5.4, 11.4.5, 10.11.15 or higher.

Credits

  • runup finder

References

Problem Types

  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor CWE