Server-side Request Forgery (SSRF) Affecting github.com/mattermost/mattermost/server/v8/channels/app package, versions >=10.11.0-rc1 <10.11.14-rc1>=11.5.0-rc1 <11.5.2-rc3>=11.6.0-rc1 <11.6.0-rc3
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-GOLANG-GITHUBCOMMATTERMOSTMATTERMOSTSERVERV8CHANNELSAPP-16873661
- published24 May 2026
- disclosed18 May 2026
- creditJuho Forsén
Introduced: 18 May 2026
CVE-2026-6333 (opens in a new tab)How to fix?
Upgrade github.com/mattermost/mattermost/server/v8/channels/app to version 10.11.14-rc1, 11.5.2-rc3, 11.6.0-rc3 or higher.
Overview
Affected versions of this package are vulnerable to Server-side Request Forgery (SSRF) via the Host header when constructing response URLs for custom slash commands. An attacker can redirect responses to a server under their control by sending a specially crafted request with a spoofed Host header.