{"id":"CVE-2026-75588","aliases":["EUVD-2026-81678","GHSA-p8rx-2r7q-5wfv"],"status":"published","title":"Mattermost Desktop App plugin popout scheme validation bypass","description":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717","severity":{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00224,"percentile":0.13115,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-1287"],"published":"2026-09-17T15:09:40Z","modified":"2026-10-28T02:30:22Z","products":[{"vendor":"mattermost","product":"mattermost"},{"vendor":"mattermost","product":"mattermost_desktop"}],"references":[{"url":"https://mattermost.com/security-updates","tags":["vendor-advisory","Vendor Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-75588","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-p8rx-2r7q-5wfv"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/75xxx/CVE-2026-75588.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-75588","title":"Mattermost Desktop App plugin popout scheme validation bypass","description":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717","status":"published","published":"2026-09-17T15:09:40.829Z","modified":"2026-09-17T19:22:50.101Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-1287"],"updated_at":"2026-11-02T14:20:07.260654Z"}],"euvd":[{"id":"EUVD-2026-81678","description":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717","status":"published","published":"2026-09-17T15:09:40Z","modified":"2026-09-17T19:22:50Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"updated_at":"2026-11-02T17:28:10.042182Z"}],"ghsa":[{"id":"GHSA-p8rx-2r7q-5wfv","title":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking...","description":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717","status":"published","published":"2026-09-17T18:31:46Z","modified":"2026-09-17T18:32:21Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-1287"],"updated_at":"2026-11-02T15:12:06.546375Z"}],"nvd":[{"id":"CVE-2026-75588","description":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717","status":"published","published":"2026-09-17T16:17:41.94Z","modified":"2026-10-13T12:02:58.587Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low","assessor":"secondary"}],"cwes":["CWE-1287"],"updated_at":"2026-11-02T14:12:49.013904Z"}],"osv":[{"id":"CVE-2026-75588","title":"Mattermost Desktop App plugin popout scheme validation bypass","description":"Mattermost Desktop App versions \u003c=6.2 6.2.2.0 fail to validate the URL scheme when checking whether a target URL is internal to the connected server, which allows a network-positioned attacker to load a plugin popout window over an insecure connection via a link using a downgraded URL scheme. Mattermost Advisory ID: MMSA-2026-00717","status":"published","published":"2026-09-17T15:09:40.829Z","modified":"2026-10-28T02:30:22.620139661Z","cvss":[{"version":"3.1","score":2.6,"vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N","level":"low"}],"cwes":["CWE-1287"],"updated_at":"2026-11-02T15:45:17.102988Z"}]}}