{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6334","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","state":"PUBLISHED","assignerShortName":"Mattermost","dateReserved":"2026-04-15T08:55:52.710Z","datePublished":"2026-05-18T06:33:56.008Z","dateUpdated":"2026-05-18T14:36:36.905Z"},"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":"Dylan Haussermann"}],"descriptions":[{"lang":"en","value":"Mattermost versions 11.5.x <= 11.5.1, 10.11.x <= 10.11.13 fail to enforce client identity binding during the OAuth authorization code redemption flow which allows an authenticated OAuth client to redeem authorization codes issued to a different client via a crafted token exchange request.. Mattermost Advisory ID: MMSA-2026-00570"}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"HIGH","privilegesRequired":"HIGH","userInteraction":"REQUIRED","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N","baseSeverity":"LOW","baseScore":3.1},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","description":"CWE-305 – Authentication Bypass by Primary Weakness","cweId":"CWE-305"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00570","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-2026-00570","defect":["https://mattermost.atlassian.net/browse/MM-67071"],"discovery":"{\"self\"=>\"https://mattermost.atlassian.net/rest/api/2/customFieldOption/10557\", \"value\"=>\"Internal\", \"id\"=>\"10557\"}"},"title":"OAuth authorization code client binding not enforced during token redemption in Mattermost","providerMetadata":{"orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost","dateUpdated":"2026-05-18T06:33:56.008Z"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-18T14:36:26.287945Z","id":"CVE-2026-6334","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":"2026-05-18T14:36:36.905Z"}}]}}