{"id":"CVE-2026-5132","state":"PUBLISHED","title":"Unbounded zlib decompression in Calls SDP WebSocket messages","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 limit size of unpacked SDP messages compressed with zlib, which allows attacker to deny service or crash server via sending many SDP messages that unpack to large size.. Mattermost Advisory ID: MMSA-2026-00643","publishedAt":"2026-09-14T10:41:42.387Z","updatedAt":"2026-09-14T11:19:45.000Z","severity":{"score":6.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","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-409"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/5xxx/CVE-2026-5132.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-5132","state":"PUBLISHED","datePublished":"2026-09-14T10:41:42.387Z","dateUpdated":"2026-09-14T11:19:45.000Z","assignerShortName":"Mattermost","assignerOrgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateReserved":"2026-03-30T09:58:00.256Z"},"containers":{"cna":{"title":"Unbounded zlib decompression in Calls SDP WebSocket messages","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 limit size of unpacked SDP messages compressed with zlib, which allows attacker to deny service or crash server via sending many SDP messages that unpack to large size.. Mattermost Advisory ID: MMSA-2026-00643"}],"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-2026-00643","tags":["vendor-advisory"]}],"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":[{"cweId":"CWE-409","lang":"en","type":"CWE","description":"CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)"}]}],"providerMetadata":{"shortName":"Mattermost","orgId":"9302f53e-dde5-4bf3-b2f2-a83f91ac0eee","dateUpdated":"2026-09-14T10:41:42.387Z"},"credits":[{"lang":"en","type":"finder","value":"daw10"}],"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-2026-00643","defect":["https://mattermost.atlassian.net/browse/MM-68130"],"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-5132","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-09-14T11:03:03.373134Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-14T11:19:45.000Z"}}]}}}