{"id":"GHSA-37j2-3vv8-cf24","summary":"Mattermost doesn't validate the TIFF IFD offset in the image header before allocating memory","details":"Mattermost versions 11.6.x \u003c= 11.6.0, 11.5.x \u003c= 11.5.2, 11.5.x \u003c= 11.5.3, 11.4.x \u003c= 11.4.4, 10.11.x \u003c= 10.11.14 fail to validate the TIFF IFD offset in the image header before allocating memory, which allows authenticated users with file upload or posting permissions to cause a denial of service (server OOM) via uploading a crafted TIFF file or posting a URL that serves one.. Mattermost Advisory ID: MMSA-2026-00648","aliases":["CVE-2026-5755","GO-2026-5835"],"modified":"2026-07-07T16:11:10.521670559Z","published":"2026-05-26T13:30:15Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2026-06-29T22:41:10Z","nvd_published_at":"2026-05-22T11:16:23Z","cwe_ids":["CWE-400"],"severity":"MODERATE"},"references":[{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-5755"},{"type":"WEB","url":"https://github.com/mattermost/mattermost/commit/d37c2d9d50b50963dabd92153adf7ed52016769a"},{"type":"PACKAGE","url":"https://github.com/mattermost/mattermost"},{"type":"WEB","url":"https://mattermost.com/security-updates"}],"affected":[{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.6.0"},{"fixed":"11.6.1"}]}],"versions":["11.6.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-37j2-3vv8-cf24/GHSA-37j2-3vv8-cf24.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.5.0"},{"fixed":"11.5.4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-37j2-3vv8-cf24/GHSA-37j2-3vv8-cf24.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"11.4.0"},{"fixed":"11.4.5"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-37j2-3vv8-cf24/GHSA-37j2-3vv8-cf24.json"}},{"package":{"name":"github.com/mattermost/mattermost-server","ecosystem":"Go","purl":"pkg:golang/github.com/mattermost/mattermost-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"10.11.0"},{"fixed":"10.11.15"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-37j2-3vv8-cf24/GHSA-37j2-3vv8-cf24.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}