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CVE-2026-3495GO-2026-5484GHSA-JX93-PF6X-874R

Unescaped variables during error page composition

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 10.11.14+incompatible, 11.5.2+incompatible, 10.11.14, 11.5.2, 8.0.0-20260310115442-5a1ea95044d, and 1 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to escape some variables that could contain malicious content during error page composition which allows an attacker with access to edit some site configuration to execute some malicious code via injecting some JS as part of those values.. Mattermost Advisory ID: MMSA-2026-00622

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Mattermost Mattermost

    From 11.5.0 · through 11.5.1; From 10.11.0 · through 10.11.13

  • github.com/mattermost/mattermost-serverGo

    From 10.11.0+incompatible · fixed in 10.11.14+incompatible; From 11.5.0+incompatible · fixed in 11.5.2+incompatible

  • github.com/mattermost/mattermost-server/v5Go

    All versions

  • github.com/mattermost/mattermost-server/v6Go

    All versions

  • github.com/mattermost/mattermost/server/v8Go

    All versions

  • github.com/mattermost/mattermost/server/v8Go

    From 10.11.0 · fixed in 10.11.14

  • github.com/mattermost/mattermost/server/v8Go

    From 11.5.0 · fixed in 11.5.2

  • github.com/mattermost/mattermost/server/v8Go

    fixed in 8.0.0-20260310115442-5a1ea95044d

  • github.com/mattermost/mattermost-serverGo

    fixed in 5.3.2-0.20260310115442-5a1ea95044dc

References 1

mattermost.com