{"id":"CVE-2023-40703","aliases":["GHSA-c37r-v8jx-7cv2"],"url":"https://o3.security/vulnerability/CVE-2023-40703","summary":"Denial of Service via specially crafted block fields in Mattermost Boards","details":"Mattermost fails to properly limit the characters allowed in different fields of a block in Mattermost Boards allowing a attacker to consume excessive resources, possibly leading to Denial of Service, by patching the field of a block using a specially crafted string. \n\n","published":"2023-11-27T09:08:31.251Z","modified":"2026-09-18T03:45:14.579755727Z","cvss":{"score":4.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"9.1.1"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"9.0.2"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost/server/v8","fixedVersion":"8.1.4"},{"ecosystem":"Go","name":"github.com/mattermost/mattermost-server/v6","fixedVersion":"7.8.13"}],"fix":null,"references":[{"type":"WEB","url":"https://mattermost.com/security-updates"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/40xxx/CVE-2023-40703.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-40703"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-18T03:45:14.579755727Z"}}