{"id":"CVE-2026-12882","state":"PUBLISHED","title":"Mattermost Markdown autolink parsing denial of service","description":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to parse Markdown autolinks with unmatched trailing closing parentheses in linear time, which allows an authenticated user with permission to create posts to cause excessive server CPU consumption and degrade availability for other users via specially crafted post or message attachment content. Mattermost Advisory ID: MMSA-2026-00703","publishedAt":"2026-09-14T10:30:39.482Z","updatedAt":"2026-09-14T11:19:45.988Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","source":"Mattermost"},"assigner":"Mattermost","products":["Mattermost Mattermost"],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.9.0","status":"affected","lessThanOrEqual":"11.9.0","versionType":"semver"},{"version":"11.8.0","status":"affected","lessThanOrEqual":"11.8.4","versionType":"semver"},{"version":"11.7.0","status":"affected","lessThanOrEqual":"11.7.7","versionType":"semver"},{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.22","versionType":"semver"},{"version":"11.10.0","status":"unaffected"},{"version":"11.9.1","status":"unaffected"},{"version":"11.8.5","status":"unaffected"},{"version":"11.7.8","status":"unaffected"},{"version":"10.11.23","status":"unaffected"}]}],"references":["https://mattermost.com/security-updates"],"weaknesses":["CWE-407"],"ingestedAt":"2026-10-29T20:10:52.580Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/12xxx/CVE-2026-12882.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-12882","state":"PUBLISHED","datePublished":"2026-09-14T10:30:39.482Z","dateUpdated":"2026-09-14T11:19:45.988Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-06-22T10:27:00.877Z"},"containers":{"cna":{"title":"Mattermost Markdown autolink parsing denial of service","descriptions":[{"lang":"en","value":"Mattermost versions 11.9.x <= 11.9.0, 11.8.x <= 11.8.4, 11.7.x <= 11.7.7, 10.11.x <= 10.11.22 fail to parse Markdown autolinks with unmatched trailing closing parentheses in linear time, which allows an authenticated user with permission to create posts to cause excessive server CPU consumption and degrade availability for other users via specially crafted post or message attachment content. Mattermost Advisory ID: MMSA-2026-00703"}],"affected":[{"vendor":"Mattermost","product":"Mattermost","defaultStatus":"unaffected","versions":[{"version":"11.9.0","status":"affected","lessThanOrEqual":"11.9.0","versionType":"semver"},{"version":"11.8.0","status":"affected","lessThanOrEqual":"11.8.4","versionType":"semver"},{"version":"11.7.0","status":"affected","lessThanOrEqual":"11.7.7","versionType":"semver"},{"version":"10.11.0","status":"affected","lessThanOrEqual":"10.11.22","versionType":"semver"},{"version":"11.10.0","status":"unaffected"},{"version":"11.9.1","status":"unaffected"},{"version":"11.8.5","status":"unaffected"},{"version":"11.7.8","status":"unaffected"},{"version":"10.11.23","status":"unaffected"}]}],"references":[{"url":"https://mattermost.com/security-updates","name":"MMSA-2026-00703","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW","version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","baseSeverity":"MEDIUM","baseScore":4.3},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-407","lang":"en","type":"CWE","description":"CWE-407: Inefficient Algorithmic Complexity"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-09-14T10:30:39.482Z"},"credits":[{"lang":"en","type":"finder","value":"Adam Korczynski"}],"solutions":[{"value":"Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8, 10.11.23 or higher.","lang":"en"}],"source":{"advisory":"MMSA-2026-00703","defect":["https://mattermost.atlassian.net/browse/MM-69407"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-12882","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-09-14T11:02:14.110168Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-14T11:19:45.988Z"}}]}}}