data/reports/GO-2026-5507.yaml

id: GO-2026-5507
modules:
    - module: github.com/mattermost/mattermost-server
      versions:
        - introduced: 10.11.0-rc1+incompatible
        - fixed: 10.11.13+incompatible
        - introduced: 11.3.0-rc1+incompatible
        - fixed: 11.3.3+incompatible
        - introduced: 11.4.0-rc1+incompatible
        - fixed: 11.4.3+incompatible
        - introduced: 11.5.0-rc1+incompatible
        - fixed: 11.5.0+incompatible
      vulnerable_at: 11.5.0-rc3+incompatible
    - module: github.com/mattermost/mattermost-server/v5
      vulnerable_at: 5.39.3
    - module: github.com/mattermost/mattermost-server/v6
      vulnerable_at: 6.7.2
    - module: github.com/mattermost/mattermost/server/v8
      versions:
        - introduced: 8.0.0-20250721062209-4952acea88ce
        - fixed: 8.0.0-20250723052842-4cb8d8940332
summary: |-
    Mattermost has session spoofing due to lack of single-use consumption of guest
    magic link tokens enforcement in github.com/mattermost/mattermost-server
cves:
    - CVE-2026-3590
ghsas:
    - GHSA-mh4x-rmrx-3hp4
references:
    - advisory: https://github.com/advisories/GHSA-mh4x-rmrx-3hp4
    - advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-3590
    - web: https://mattermost.com/security-updates
notes:
    - fix: 'github.com/mattermost/mattermost/server/v8: could not add vulnerable_at: could not find tagged version between introduced and fixed'
source:
    id: GHSA-mh4x-rmrx-3hp4
    created: 2026-06-25T15:46:21.73096553-04:00
review_status: UNREVIEWED