CVE-2026-10819

Summary

Mattermost versions 11.6.x <= 11.6.5, 10.11.x <= 10.11.20, 11.8.x <= 11.8.1, 11.7.x <= 11.7.4 fail to limit the number of frames and enforce the file size cap on animated GIF uploads, which allows an authenticated attacker to cause a denial of service via a crafted animated GIF uploaded as a custom emoji.. Mattermost Advisory ID: MMSA-2026-00695

Affected Software

VendorProductVersion RangeStatus
MattermostMattermost11.6.0 <= 11.6.5affected
MattermostMattermost10.11.0 <= 10.11.20affected
MattermostMattermost11.8.0 <= 11.8.1affected
MattermostMattermost11.7.0 <= 11.7.4affected
MattermostMattermost11.9.0unaffected
MattermostMattermost11.6.6unaffected
MattermostMattermost10.11.21unaffected
MattermostMattermost11.8.2unaffected
MattermostMattermost11.7.5unaffected

Weaknesses

  • CWE-409: CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)

ADP Enrichment

CISA ADP Vulnrichment

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

References