{"id":"CVE-2020-16969","aliases":["EUVD-2020-8927","GHSA-hx67-2mh4-8cj2"],"status":"published","title":"Microsoft Exchange Information Disclosure Vulnerability","description":"\u003cp\u003eAn information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.\u003c/p\u003e\n\u003cp\u003eTo exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.\u003c/p\u003e\n\u003cp\u003eThe security update corrects the way that Exchange handles these token validations.\u003c/p\u003e","severity":{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L/E:P/RL:O/RC:C","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.0273,"percentile":0.86205,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2020-10-16T22:18:07Z","modified":"2026-06-17T02:58:22Z","products":[{"vendor":"microsoft","product":"exchange_server"},{"vendor":"microsoft","product":"microsoft exchange server 2013 cumulative update 23"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 17"},{"vendor":"microsoft","product":"microsoft exchange server 2016 cumulative update 18"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 6"},{"vendor":"microsoft","product":"microsoft exchange server 2019 cumulative update 7"}],"references":[{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16969","tags":["x_refsource_MISC","x_transferred","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2020-16969"},{"url":"https://github.com/advisories/GHSA-hx67-2mh4-8cj2"}],"sources":{"cve":[{"id":"CVE-2020-16969","title":"Microsoft Exchange Information Disclosure Vulnerability","description":"\u003cp\u003eAn information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.\u003c/p\u003e\n\u003cp\u003eTo exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.\u003c/p\u003e\n\u003cp\u003eThe security update corrects the way that Exchange handles these token validations.\u003c/p\u003e","status":"published","published":"2020-10-16T22:18:07Z","modified":"2024-08-04T13:45:34.738Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L/E:P/RL:O/RC:C","level":"high","assessor":"cna"}],"updated_at":"2026-11-02T14:35:59.116379Z"}],"euvd":[{"id":"EUVD-2020-8927","description":"\u003cp\u003eAn information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.\u003c/p\u003e\n\u003cp\u003eTo exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.\u003c/p\u003e\n\u003cp\u003eThe security update corrects the way that Exchange handles these token validations.\u003c/p\u003e","status":"published","published":"2020-10-16T22:18:07Z","modified":"2024-08-04T13:45:34Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L/E:P/RL:O/RC:C","level":"high"}],"updated_at":"2026-11-03T03:07:27.538796Z"}],"ghsa":[{"id":"GHSA-hx67-2mh4-8cj2","title":"An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when...","description":"An information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages, aka 'Microsoft Exchange Information Disclosure Vulnerability'.","status":"published","published":"2022-05-24T17:31:02Z","modified":"2024-01-09T05:05:19Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L","level":"high"}],"updated_at":"2026-11-02T14:55:22.44362Z"}],"nvd":[{"id":"CVE-2020-16969","description":"\u003cp\u003eAn information disclosure vulnerability exists in how Microsoft Exchange validates tokens when handling certain messages. An attacker who successfully exploited the vulnerability could use this to gain further information from a user.\u003c/p\u003e\n\u003cp\u003eTo exploit the vulnerability, an attacker could include specially crafted OWA messages that could be loaded, without warning or filtering, from the attacker-controlled URL. This callback vector provides an information disclosure tactic used in web beacons and other types of tracking systems.\u003c/p\u003e\n\u003cp\u003eThe security update corrects the way that Exchange handles these token validations.\u003c/p\u003e","status":"published","published":"2020-10-16T23:15:16.743Z","modified":"2026-06-17T02:58:22.897Z","cvss":[{"version":"3.1","score":7.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:06:19.351389Z"}]}}