{"id":"CVE-2021-37845","aliases":["EUVD-2021-24324","GHSA-hh3j-j42w-mrpm","UBUNTU-CVE-2021-37845"],"status":"published","title":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can...","description":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of \"The STARTTLS command is only valid in non-authenticated state.\" in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.","severity":{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.00665,"percentile":0.52137,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2023-05-29T00:00:00Z","modified":"2026-06-17T04:01:11Z","affected":[{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"citadel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["9.01-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"citadel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["911-1","917-2"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"citadel","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["917-3","917-4"]}],"products":[{"vendor":"citadel","product":"webcit"}],"references":[{"url":"http://uncensored.citadel.org/dotgoto?room=Citadel%20Security","tags":["x_transferred","Issue Tracking"]},{"url":"https://uncensored.citadel.org/msg/2099264259","tags":["x_transferred","Exploit"]},{"url":"https://nostarttls.secvuln.info/","tags":["x_transferred","Broken Link","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-37845"},{"url":"https://nostarttls.secvuln.info"},{"url":"https://github.com/advisories/GHSA-hh3j-j42w-mrpm"},{"url":"https://ubuntu.com/security/CVE-2021-37845","tags":["report"]},{"url":"https://uncensored.citadel.org/readfwd?go=Citadel","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-37845","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-37845","description":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of \"The STARTTLS command is only valid in non-authenticated state.\" in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.","status":"published","published":"2023-05-29T00:00:00Z","modified":"2025-01-14T17:46:34.428Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"adp"}],"updated_at":"2026-11-02T14:32:58.359368Z"}],"euvd":[{"id":"EUVD-2021-24324","description":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of \"The STARTTLS command is only valid in non-authenticated state.\" in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.","status":"published","published":"2023-05-29T00:00:00Z","modified":"2025-01-14T17:46:34Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-03T00:04:19.424496Z"}],"ghsa":[{"id":"GHSA-hh3j-j42w-mrpm","title":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can...","description":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of \"The STARTTLS command is only valid in non-authenticated state.\" in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.","status":"published","published":"2023-05-29T21:30:16Z","modified":"2024-04-04T04:22:43Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T14:56:23.412856Z"}],"nvd":[{"id":"CVE-2021-37845","description":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of \"The STARTTLS command is only valid in non-authenticated state.\" in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.","status":"published","published":"2023-05-29T19:15:09.527Z","modified":"2026-06-17T04:01:11.643Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"primary"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"}],"updated_at":"2026-11-02T14:07:07.764332Z"}],"osv":[{"id":"UBUNTU-CVE-2021-37845","description":"An issue was discovered in Citadel through webcit-932. A meddler-in-the-middle attacker can fixate their own session during the cleartext phase before a STARTTLS command (a violation of \"The STARTTLS command is only valid in non-authenticated state.\" in RFC2595). This potentially allows an attacker to cause a victim's e-mail messages to be stored into an attacker's IMAP mailbox, but depends on details of the victim's client behavior.","status":"published","published":"2023-05-29T19:15:00Z","modified":"2025-10-24T04:50:27Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"},{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T15:54:28.526929Z"}]}}