{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-4635","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","state":"PUBLISHED","assignerShortName":"Mattermost","dateReserved":"2026-03-23T08:41:57.555Z","datePublished":"2026-05-22T10:28:47.634Z","dateUpdated":"2026-05-22T12:06:16.773Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Mattermost","vendor":"Mattermost","versions":[{"lessThanOrEqual":"11.6.0","status":"affected","version":"11.6.0","versionType":"semver"},{"lessThanOrEqual":"11.5.3","status":"affected","version":"11.5.0","versionType":"semver"},{"lessThanOrEqual":"11.4.4","status":"affected","version":"11.4.0","versionType":"semver"},{"lessThanOrEqual":"10.11.14","status":"affected","version":"10.11.0","versionType":"semver"},{"version":"11.7.0","status":"unaffected"},{"version":"11.6.1","status":"unaffected"},{"version":"11.5.4","status":"unaffected"},{"version":"11.4.5","status":"unaffected"},{"version":"10.11.15","status":"unaffected"}]}],"credits":[{"lang":"en","type":"finder","value":"daw10"}],"descriptions":[{"lang":"en","value":"Mattermost versions 11.6.x <= 11.6.0, 11.5.x <= 11.5.3, 11.4.x <= 11.4.4, 10.11.x <= 10.11.14 fail to archive the channel before removing persistent notifications which allows authenticated user to crash the server via timing the creation of persistent notification message between the server deleting existing persistent notifications and archiving the channel.. Mattermost Advisory ID: MMSA-2026-00637"}],"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-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')","cweId":"CWE-362"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00637","tags":["vendor-advisory"]}],"solutions":[{"value":"Update Mattermost to versions 11.7.0, 11.6.1, 11.5.4, 11.4.5, 10.11.15 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00637","defect":["https://mattermost.atlassian.net/browse/MM-68023"],"discovery":"EXTERNAL"},"title":"Persistent notification timing attack causing server denial of service","providerMetadata":{"orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","shortName":"Mattermost","dateUpdated":"2026-05-22T10:28:47.634Z"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-22T12:06:11.038792Z","id":"CVE-2026-4635","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":"2026-05-22T12:06:16.773Z"}}]}}