Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582
Metrics
Affected Vendors & Products
References
| Link | Providers |
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| https://mattermost.com/security-updates |
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History
Tue, 19 May 2026 18:15:00 +0000
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| Metrics |
ssvc
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Tue, 19 May 2026 18:00:00 +0000
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| First Time appeared |
Mattermost mattermost Server
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| CPEs | cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Mattermost mattermost Server
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Mon, 18 May 2026 10:45:00 +0000
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| First Time appeared |
Mattermost
Mattermost mattermost |
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| Vendors & Products |
Mattermost
Mattermost mattermost |
Mon, 18 May 2026 09:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582 | |
| Title | SSRF via Host Header Spoofing in Custom Slash Commands | |
| Weaknesses | CWE-918 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: Mattermost
Published: 2026-05-18T08:41:29.342Z
Updated: 2026-05-19T17:19:42.466Z
Reserved: 2026-04-15T08:51:33.309Z
Link: CVE-2026-6333
Updated: 2026-05-18T14:36:17.582Z
Status : Analyzed
Published: 2026-05-18T09:16:23.430
Modified: 2026-05-19T17:51:43.453
Link: CVE-2026-6333
No data.