{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-4054","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","state":"PUBLISHED","assignerShortName":"Mattermost","dateReserved":"2026-03-12T16:08:33.686Z","datePublished":"2026-05-15T18:32:44.388Z","dateUpdated":"2026-05-15T20:23:24.121Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"11.5.1","status":"affected","version":"11.5.0","versionType":"semver"},{"lessThanOrEqual":"10.11.13","status":"affected","version":"10.11.0","versionType":"semver"},{"lessThanOrEqual":"11.4.3","status":"affected","version":"11.4.0","versionType":"semver"},{"version":"11.6.0","status":"unaffected"},{"version":"11.5.2","status":"unaffected"},{"version":"10.11.14","status":"unaffected"},{"version":"11.4.4","status":"unaffected"}]}],"credits":[{"lang":"en","type":"finder","value":"mk7120"}],"descriptions":[{"lang":"en","value":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13, 11.4.x <= 11.4.3 Fail to validate the response body of proxied images, which allows a remote attacker to enact client-side DoS via an SVG file served from an attacker-controlled origin under a non-SVG Content-Type header (e.g. image/png) embedded in an og:image meta tag or Markdown image link.. Mattermost Advisory ID: MMSA-2026-00630"}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L","baseSeverity":"MEDIUM","baseScore":4.3},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-754: Improper Check for Unusual or Exceptional Conditions","cweId":"CWE-754"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00630","tags":["vendor-advisory"]}],"solutions":[{"value":"Update Mattermost to versions 11.6.0, 11.5.2, 10.11.14, 11.4.4 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00630","defect":["https://mattermost.atlassian.net/browse/MM-67871"],"discovery":"EXTERNAL"},"title":"SVG content served through Mattermost image proxy despite Content-Type restrictions causes client-side denial of service","providerMetadata":{"orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost","dateUpdated":"2026-05-15T18:32:44.388Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-15T20:23:14.754503Z","id":"CVE-2026-4054","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":"2026-05-15T20:23:24.121Z"}}]}}