CVE-2026-10819

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-10819", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-06-04T07:34:33.428Z", "datePublished": "2026-07-27T14:15:25.000Z", "dateUpdated": "2026-07-27T15:05:28.394Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.6.5", "status": "affected", "version": "11.6.0", "versionType": "semver"}, {"lessThanOrEqual": "10.11.20", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"lessThanOrEqual": "11.8.1", "status": "affected", "version": "11.8.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.4", "status": "affected", "version": "11.7.0", "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"}]}], "credits": [{"lang": "en", "type": "finder", "value": "Adam Korczynski"}], "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"}], "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": [{"lang": "en", "type": "CWE", "description": "CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)", "cweId": "CWE-409"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00695", "tags": ["vendor-advisory"]}], "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"}, "title": "Mattermost Server Denial of Service via Animated GIF Emoji Upload", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-07-27T14:15:25.000Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"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"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-27T15:05:28.394Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-10819", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-07-27T15:05:17.249105Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-27T15:05:23.347Z"}}], "cna": {"title": "Mattermost Server Denial of Service via Animated GIF Emoji Upload", "source": {"defect": ["https://mattermost.atlassian.net/browse/MM-69125"], "advisory": "MMSA-2026-00695", "discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "Adam Korczynski"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 6.5, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "NONE"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "11.6.0", "versionType": "semver", "lessThanOrEqual": "11.6.5"}, {"status": "affected", "version": "10.11.0", "versionType": "semver", "lessThanOrEqual": "10.11.20"}, {"status": "affected", "version": "11.8.0", "versionType": "semver", "lessThanOrEqual": "11.8.1"}, {"status": "affected", "version": "11.7.0", "versionType": "semver", "lessThanOrEqual": "11.7.4"}, {"status": "unaffected", "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"}], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "Update Mattermost to versions 11.9.0, 11.6.6, 10.11.21, 11.8.2, 11.7.5 or higher."}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00695", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "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"}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-409", "description": "CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)"}]}], "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-07-27T14:15:25.000Z"}}}, "cveMetadata": {"cveId": "CVE-2026-10819", "state": "PUBLISHED", "dateUpdated": "2026-07-27T15:05:28.394Z", "dateReserved": "2026-06-04T07:34:33.428Z", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "datePublished": "2026-07-27T14:15:25.000Z", "assignerShortName": "Mattermost"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.6.5", "status": "affected", "version": "11.6.0", "versionType": "semver"}, {"lessThanOrEqual": "10.11.20", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"lessThanOrEqual": "11.8.1", "status": "affected", "version": "11.8.0", "versionType": "semver"}, {"lessThanOrEqual": "11.7.4", "status": "affected", "version": "11.7.0", "versionType": "semver"}, {"status": "unaffected", "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"}]}], "source": "responsibledisclosure@mattermost.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "E077E0D9-468B-463D-B269-9445B309D2D5", "versionEndExcluding": "10.11.21", "versionStartIncluding": "10.11.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "919293F0-3971-499D-A0BE-72A85AED3E59", "versionEndExcluding": "11.6.6", "versionStartIncluding": "11.6.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "55EDBAD9-FC4F-4EA6-BE82-DD74022CA93B", "versionEndExcluding": "11.7.5", "versionStartIncluding": "11.7.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:mattermost:mattermost_server:*:*:*:*:*:*:*:*", "matchCriteriaId": "550D48A4-3830-49F2-BC35-406E3889997B", "versionEndExcluding": "11.8.2", "versionStartIncluding": "11.8.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "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"}], "id": "CVE-2026-10819", "lastModified": "2026-08-03T15:23:50.490", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-10819", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-07-27T15:05:17.249105Z", "version": "2.0.3"}}]}, "published": "2026-07-27T15:16:46.770", "references": [{"source": "responsibledisclosure@mattermost.com", "tags": ["Vendor Advisory"], "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-409"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.6.0,11.6.5]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[10.11.0,10.11.20]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.8.0,11.8.1]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.7.0,11.7.4]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.9.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.6.6"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "10.11.21"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.8.2"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.7.5"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Mattermost", "source": "cna", "vendor": "Mattermost"}, "product": "mattermost", "vendor": "mattermost"}], "created": "2026-07-27T15:22:43.516070+00:00", "updated": "2026-08-04T14:00:03.943946+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}