{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-2455", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "state": "PUBLISHED", "assignerShortName": "Mattermost", "dateReserved": "2026-02-13T10:45:36.473Z", "datePublished": "2026-03-16T14:53:31.280Z", "dateUpdated": "2026-03-16T18:38:07.619Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Mattermost", "vendor": "Mattermost", "versions": [{"lessThanOrEqual": "11.3.0", "status": "affected", "version": "11.3.0", "versionType": "semver"}, {"lessThanOrEqual": "11.2.2", "status": "affected", "version": "11.2.0", "versionType": "semver"}, {"lessThanOrEqual": "10.11.10", "status": "affected", "version": "10.11.0", "versionType": "semver"}, {"version": "11.4.0", "status": "unaffected"}, {"version": "11.3.1", "status": "unaffected"}, {"version": "11.2.3", "status": "unaffected"}, {"version": "10.11.11", "status": "unaffected"}]}], "credits": [{"lang": "en", "type": "finder", "value": "winfunc"}], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation which allows an attacker to perform SSRF attacks against internal services via IPv4-mapped IPv6 literals (e.g., [::ffff:127.0.0.1]).. Mattermost Advisory ID: MMSA-2026-00585"}], "metrics": [{"cvssV3_1": {"attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE", "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "baseSeverity": "MEDIUM", "baseScore": 4.3}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "description": "CWE-918: Server-Side Request Forgery (SSRF)", "cweId": "CWE-918"}]}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00585", "tags": ["vendor-advisory"]}], "solutions": [{"value": "Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3, 10.11.11 or higher.", "lang": "en"}], "source": {"advisory": "MMSA-2026-00585", "defect": ["https://mattermost.atlassian.net/browse/MM-67262"], "discovery": "EXTERNAL"}, "title": "SSRF bypass via IPv4-mapped IPv6 literals", "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-03-16T14:53:31.280Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-03-16T18:37:36.914842Z", "id": "CVE-2026-2455", "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": "2026-03-16T18:38:07.619Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-2455", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-03-16T18:37:36.914842Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-16T18:38:00.408Z"}}], "cna": {"title": "SSRF bypass via IPv4-mapped IPv6 literals", "source": {"defect": ["https://mattermost.atlassian.net/browse/MM-67262"], "advisory": "MMSA-2026-00585", "discovery": "EXTERNAL"}, "credits": [{"lang": "en", "type": "finder", "value": "winfunc"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 4.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "LOW"}, "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "affected": [{"vendor": "Mattermost", "product": "Mattermost", "versions": [{"status": "affected", "version": "11.3.0", "versionType": "semver", "lessThanOrEqual": "11.3.0"}, {"status": "affected", "version": "11.2.0", "versionType": "semver", "lessThanOrEqual": "11.2.2"}, {"status": "affected", "version": "10.11.0", "versionType": "semver", "lessThanOrEqual": "10.11.10"}, {"status": "unaffected", "version": "11.4.0"}, {"status": "unaffected", "version": "11.3.1"}, {"status": "unaffected", "version": "11.2.3"}, {"status": "unaffected", "version": "10.11.11"}], "defaultStatus": "unaffected"}], "solutions": [{"lang": "en", "value": "Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3, 10.11.11 or higher."}], "references": [{"url": "https://mattermost.com/security-updates", "name": "MMSA-2026-00585", "tags": ["vendor-advisory"]}], "x_generator": {"engine": "cvelib 1.8.0"}, "descriptions": [{"lang": "en", "value": "Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation which allows an attacker to perform SSRF attacks against internal services via IPv4-mapped IPv6 literals (e.g., [::ffff:127.0.0.1]).. Mattermost Advisory ID: MMSA-2026-00585"}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-918", "description": "CWE-918: Server-Side Request Forgery (SSRF)"}]}], "providerMetadata": {"orgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "shortName": "Mattermost", "dateUpdated": "2026-03-16T14:53:31.280Z"}}}, "cveMetadata": {"cveId": "CVE-2026-2455", "state": "PUBLISHED", "dateUpdated": "2026-03-16T18:38:07.619Z", "dateReserved": "2026-02-13T10:45:36.473Z", "assignerOrgId": "9302f53e-dde5-4bf3-b2f2-a83f91ac0eee", "datePublished": "2026-03-16T14:53:31.280Z", "assignerShortName": "Mattermost"}, "dataVersion": "5.2"}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "Mattermost versions 11.3.x <= 11.3.0, 11.2.x <= 11.2.2, 10.11.x <= 10.11.10 fail to canonicalize IPv4-mapped IPv6 addresses before reserved IP validation which allows an attacker to perform SSRF attacks against internal services via IPv4-mapped IPv6 literals (e.g., [::ffff:127.0.0.1]).. Mattermost Advisory ID: MMSA-2026-00585"}], "id": "CVE-2026-2455", "lastModified": "2026-03-17T14:20:01.670", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}, "published": "2026-03-16T15:16:22.277", "references": [{"source": "responsibledisclosure@mattermost.com", "url": "https://mattermost.com/security-updates"}], "sourceIdentifier": "responsibledisclosure@mattermost.com", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-918"}], "source": "responsibledisclosure@mattermost.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,11.3.0]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[11.2.0,11.2.2]"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[10.11.0,10.11.10]"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.4.0"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.3.1"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "11.2.3"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "10.11.11"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Mattermost", "source": "cna", "vendor": "Mattermost"}, "product": "mattermost", "vendor": "mattermost"}], "created": "2026-03-17T09:52:43.976775+00:00", "updated": "2026-03-17T09:52:43.976880+00:00", "vendors": ["mattermost", "mattermost$PRODUCT$mattermost"]}