{"id":"CVE-2026-3590","state":"PUBLISHED","title":"Race Condition in Guest Magic Link Authentication Allows Token Reuse","description":"Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624","publishedAt":"2026-04-15T11:00:14.880Z","updatedAt":"2026-04-15T14:00:27.030Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.12","versionType":"semver"},{"version":"11.5.0","status":"affected","lessThanOrEqual":"11.5.0","versionType":"semver"},{"version":"11.4.0","status":"affected","lessThanOrEqual":"11.4.2","versionType":"semver"},{"version":"11.3.0","status":"affected","lessThanOrEqual":"11.3.2","versionType":"semver"},{"version":"11.6.0","status":"unaffected"},{"version":"10.11.13","status":"unaffected"},{"version":"11.5.1","status":"unaffected"},{"version":"11.4.3","status":"unaffected"},{"version":"11.3.3","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-367"],"ingestedAt":"2026-10-29T20:11:50.837Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/3xxx/CVE-2026-3590.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-3590","state":"PUBLISHED","datePublished":"2026-04-15T11:00:14.880Z","dateUpdated":"2026-04-15T14:00:27.030Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-03-05T11:34:57.712Z"},"containers":{"cna":{"title":"Race Condition in Guest Magic Link Authentication Allows Token Reuse","descriptions":[{"lang":"en","value":"Mattermost versions 10.11.x <= 10.11.12, 11.5.x <= 11.5.0, 11.4.x <= 11.4.2, 11.3.x <= 11.3.2 fail to enforce atomic single-use consumption of guest magic link tokens, which allows an attacker with access to a valid magic link to establish multiple independent authenticated sessions via concurrent requests.. Mattermost Advisory ID: MMSA-2026-00624"}],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.12","versionType":"semver"},{"version":"11.5.0","status":"affected","lessThanOrEqual":"11.5.0","versionType":"semver"},{"version":"11.4.0","status":"affected","lessThanOrEqual":"11.4.2","versionType":"semver"},{"version":"11.3.0","status":"affected","lessThanOrEqual":"11.3.2","versionType":"semver"},{"version":"11.6.0","status":"unaffected"},{"version":"10.11.13","status":"unaffected"},{"version":"11.5.1","status":"unaffected"},{"version":"11.4.3","status":"unaffected"},{"version":"11.3.3","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00624","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"LOW","availabilityImpact":"NONE","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","baseSeverity":"MEDIUM","baseScore":6.5},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-367","lang":"en","type":"CWE","description":"CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-04-15T11:00:14.880Z"},"credits":[{"lang":"en","type":"finder","value":"Edgar Bellot Micó"}],"solutions":[{"value":"Update Mattermost to versions 11.6.0, 10.11.13, 11.5.1, 11.4.3, 11.3.3 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00624","defect":["https://mattermost.atlassian.net/browse/MM-67791"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-04-15T14:00:15.919479Z","id":"CVE-2026-3590","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-04-15T14:00:27.030Z"}}]}}}