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Medium severity5.5NVD Advisory· Published Sep 22, 2026· Updated Oct 7, 2026

CVE-2026-96259

CVE-2026-96259

Description

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

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

2
  • Mattermost/Mattermostllm-fuzzy2 versions
    <=11.9.1, <=11.8.5, <=11.7.10, <=11.10.1+ 1 more
    • (no CPE)range: <=11.9.1, <=11.8.5, <=11.7.10, <=11.10.1
    • cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*range: >=11.7.0,<11.7.11

Patches

Vulnerability mechanics

References

1

News mentions

1