{"id":"CVE-2026-55009","aliases":["EUVD-2026-44027","GHSA-78c8-h6hm-94hg"],"status":"published","title":"Microsoft Exchange Server Elevation of Privilege Vulnerability","description":"Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.","severity":{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.02513,"percentile":0.84909,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-502"],"published":"2026-07-14T17:05:02Z","modified":"2026-11-01T17:32:40Z","products":[{"vendor":"microsoft","product":"exchange_server"},{"vendor":"microsoft","product":"exchange_server_subscription_edition"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 23"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 14"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 15"},{"vendor":"microsoft","product":"microsoft exchange server subscription edition rtm"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-55009","tags":["vendor-advisory","patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55009"},{"url":"https://github.com/advisories/GHSA-78c8-h6hm-94hg"}],"sources":{"cve":[{"id":"CVE-2026-55009","title":"Microsoft Exchange Server Elevation of Privilege Vulnerability","description":"Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.","status":"published","published":"2026-07-14T17:05:02.147Z","modified":"2026-11-01T17:32:40.32Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","level":"high","assessor":"cna"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:20:11.925815Z"}],"euvd":[{"id":"EUVD-2026-44027","description":"Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.","status":"published","published":"2026-07-14T17:05:02Z","modified":"2026-11-01T17:32:40Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C","level":"high"}],"updated_at":"2026-11-02T16:58:49.161713Z"}],"ghsa":[{"id":"GHSA-78c8-h6hm-94hg","title":"Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to...","description":"Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.","status":"published","published":"2026-07-14T18:32:10Z","modified":"2026-07-14T18:32:10Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T15:09:28.277582Z"}],"nvd":[{"id":"CVE-2026-55009","description":"Deserialization of untrusted data in Microsoft Exchange Server allows an authorized attacker to elevate privileges locally.","status":"published","published":"2026-07-14T17:17:08.883Z","modified":"2026-07-24T19:19:42.72Z","cvss":[{"version":"3.1","score":7.8,"vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-502"],"updated_at":"2026-11-02T14:12:29.489525Z"}]}}