{"id":"CVE-2021-40906","aliases":["EUVD-2021-28061","GHSA-jv73-q4rg-p7qh","UBUNTU-CVE-2021-40906","USN-5527-1"],"status":"published","title":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web...","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","severity":{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.00998,"percentile":0.62989,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":true},"cwes":["CWE-79"],"published":"2022-03-25T22:20:04Z","modified":"2026-10-24T10:30:59Z","exploits":[{"source":"pocgithub","id":"Edgarloyola/CVE-2021-40906","title":"Edgarloyola/CVE-2021-40906","date":"2021-10-12","url":"https://github.com/Edgarloyola/CVE-2021-40906"}],"fixes":[{"ecosystem":"Ubuntu:18.04:LTS","package":"check-mk","fixed_in":["1.2.8p16-1ubuntu0.2"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"check-mk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.8p16-1ubuntu0.2"}]}],"versions":["1.2.8p16-1ubuntu0.1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"check-mk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.2.8p16-1ubuntu0.2"}]}],"versions":["1.2.8p16-1ubuntu0.1"],"bundled":5}],"products":[{"vendor":"checkmk","product":"checkmk"},{"vendor":"tribe29","product":"checkmk"}],"references":[{"url":"https://github.com/Edgarloyola/CVE-2021-40906","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-40906"},{"url":"http://checkmk.com"},{"url":"https://github.com/advisories/GHSA-jv73-q4rg-p7qh"},{"url":"https://ubuntu.com/security/CVE-2021-40906","tags":["report"]},{"url":"https://checkmk.com/werk/13192","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-5527-1","tags":["advisory"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-40906","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2017-9781","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2017-14955","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2021-36563","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2022-24565","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-40906","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","status":"published","published":"2022-03-25T22:20:04Z","modified":"2026-07-09T00:14:50.239Z","updated_at":"2026-11-02T14:33:01.495293Z"}],"euvd":[{"id":"EUVD-2021-28061","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","status":"published","published":"2022-03-25T22:20:04Z","modified":"2026-07-09T00:14:50Z","updated_at":"2026-11-02T18:20:08.60883Z"}],"ghsa":[{"id":"GHSA-jv73-q4rg-p7qh","title":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web...","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","status":"published","published":"2022-03-27T00:00:38Z","modified":"2023-01-27T05:01:04Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:41:48.523978Z"}],"nvd":[{"id":"CVE-2021-40906","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","status":"published","published":"2022-03-25T23:15:08.287Z","modified":"2026-07-09T01:17:02.513Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:07:05.581807Z"}],"osv":[{"id":"CVE-2021-40906","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","status":"published","published":"2022-03-25T23:15:08.287Z","modified":"2026-10-24T10:30:59.205939927Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:21.249056Z"},{"id":"UBUNTU-CVE-2021-40906","description":"CheckMK Raw Edition software (versions 1.5.0 to 1.6.0) does not sanitise the input of a web service parameter that is in an unauthenticated zone. This Reflected XSS allows an attacker to open a backdoor on the device with HTML content and interpreted by the browser (such as JavaScript or other client-side scripts) or to steal the session cookies of a user who has previously authenticated via a man in the middle. Successful exploitation requires access to the web service resource without authentication.","status":"published","published":"2022-03-25T23:15:00Z","modified":"2026-02-04T02:27:19.713922Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"updated_at":"2026-11-02T15:54:29.220315Z"},{"id":"USN-5527-1","title":"check-mk vulnerabilities","description":"It was discovered that Checkmk incorrectly handled authentication. An attacker \ncould possibly use this issue to cause a race condition leading to information \ndisclosure. (CVE-2017-14955)\n\nIt was discovered that Checkmk incorrectly handled certain inputs. An attacker\ncould use these cross-site scripting issues to inject arbitrary html or \njavascript code to obtain sensitive information including user information, \nsession cookies and valid credentials. (CVE-2017-9781, CVE-2021-36563, \nCVE-2021-40906, CVE-2022-24565)\n","status":"published","published":"2022-07-20T08:36:48Z","modified":"2026-02-10T04:42:42Z","updated_at":"2026-11-02T16:58:16.20937Z"}]}}