{"id":"CVE-2026-10819","state":"PUBLISHED","title":"Mattermost Server Denial of Service via Animated GIF Emoji Upload","description":"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","publishedAt":"2026-07-27T14:15:25.000Z","updatedAt":"2026-07-27T15:05:28.394Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.6.0","status":"affected","lessThanOrEqual":"11.6.5","versionType":"semver"},{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.20","versionType":"semver"},{"version":"11.8.0","status":"affected","lessThanOrEqual":"11.8.1","versionType":"semver"},{"version":"11.7.0","status":"affected","lessThanOrEqual":"11.7.4","versionType":"semver"},{"version":"11.9.0","status":"unaffected"},{"version":"11.6.6","status":"unaffected"},{"version":"10.11.21","status":"unaffected"},{"version":"11.8.2","status":"unaffected"},{"version":"11.7.5","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-409"],"ingestedAt":"2026-10-29T20:10:33.477Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/10xxx/CVE-2026-10819.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-10819","state":"PUBLISHED","datePublished":"2026-07-27T14:15:25.000Z","dateUpdated":"2026-07-27T15:05:28.394Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-06-04T07:34:33.428Z"},"containers":{"cna":{"title":"Mattermost Server Denial of Service via Animated GIF Emoji Upload","descriptions":[{"lang":"en","value":"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":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.6.0","status":"affected","lessThanOrEqual":"11.6.5","versionType":"semver"},{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.20","versionType":"semver"},{"version":"11.8.0","status":"affected","lessThanOrEqual":"11.8.1","versionType":"semver"},{"version":"11.7.0","status":"affected","lessThanOrEqual":"11.7.4","versionType":"semver"},{"version":"11.9.0","status":"unaffected"},{"version":"11.6.6","status":"unaffected"},{"version":"10.11.21","status":"unaffected"},{"version":"11.8.2","status":"unaffected"},{"version":"11.7.5","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00695","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseSeverity":"MEDIUM","baseScore":6.5},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-409","lang":"en","type":"CWE","description":"CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-07-27T14:15:25.000Z"},"credits":[{"lang":"en","type":"finder","value":"Adam Korczynski"}],"solutions":[{"value":"Update Mattermost to versions 11.9.0, 11.6.6, 10.11.21, 11.8.2, 11.7.5 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00695","defect":["https://mattermost.atlassian.net/browse/MM-69125"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-27T15:05:17.249105Z","id":"CVE-2026-10819","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-27T15:05:28.394Z"}}]}}}