{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6333","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","state":"PUBLISHED","assignerShortName":"Mattermost","dateReserved":"2026-04-15T08:51:33.309Z","datePublished":"2026-05-18T08:41:29.342Z","dateUpdated":"2026-05-19T17:19:42.466Z"},"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"},{"version":"11.6.0","status":"unaffected"},{"version":"11.5.2","status":"unaffected"},{"version":"10.11.14","status":"unaffected"}]}],"credits":[{"lang":"en","type":"finder","value":"Juho Forsén"}],"descriptions":[{"lang":"en","value":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to validate the Host header when constructing response URLs for custom slash commands which allows an authenticated attacker to redirect slash command responses to an attacker-controlled server via a spoofed Host header.. Mattermost Advisory ID: MMSA-2026-00582"}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"LOW","userInteraction":"NONE","scope":"CHANGED","confidentialityImpact":"NONE","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N","baseSeverity":"LOW","baseScore":3.5},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-918: Server-Side Request Forgery (SSRF)","cweId":"CWE-918"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00582","tags":["vendor-advisory"]}],"solutions":[{"value":"Update Mattermost to versions 11.6.0, 11.5.2, 10.11.14 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00582","defect":["https://mattermost.atlassian.net/browse/MM-67142"],"discovery":"{\"self\"=>\"https://mattermost.atlassian.net/rest/api/2/customFieldOption/10557\", \"value\"=>\"Internal\", \"id\"=>\"10557\"}"},"title":"SSRF via Host Header Spoofing in Custom Slash Commands","providerMetadata":{"orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost","dateUpdated":"2026-05-18T08:41:29.342Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-18T14:36:12.538799Z","id":"CVE-2026-6333","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":"2026-05-19T17:19:42.466Z"}}]}}