CVE-2026-96259

Summary

Mattermost versions 11.9.x <= 11.9.1, 11.8.x <= 11.8.5, 11.7.x <= 11.7.10, 11.10.x <= 11.10.1 fail to apply the internal-connection filter to OAuth endpoint requests, which allows a System Administrator to make the server issue requests to internal network addresses and read the responses via the configured OAuth token and userinfo endpoints.. Mattermost Advisory ID: MMSA-2026-00776

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.9.0 <= 11.9.1affected
MattermostMattermost11.8.0 <= 11.8.5affected
MattermostMattermost11.7.0 <= 11.7.10affected
MattermostMattermost11.10.0 <= 11.10.1affected
MattermostMattermost11.11.0unaffected
MattermostMattermost11.9.2unaffected
MattermostMattermost11.8.6unaffected
MattermostMattermost11.7.11unaffected
MattermostMattermost11.10.2unaffected

Weaknesses

  • CWE-918: CWE-918: Server-Side Request Forgery (SSRF)

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References