{"id":"CVE-2019-16216","url":"https://www.cyber-defence.io/tools/cve/CVE-2019-16216","generatedAt":"2026-10-28T22:21:20.143Z","title":"A user who is logged into the server could upload files of certain types to mount a stored cross-site scripting attack on other logged-in users.","description":"Zulip server before 2.0.5 incompletely validated the MIME types of uploaded files. A user who is logged into the server could upload files of certain types to mount a stored cross-site scripting attack on other logged-in users. On a Zulip server using the default local uploads backend, the attack is only effective against browsers lacking support for Content-Security-Policy such as Internet Explorer 11. On a Zulip server using the S3 uploads backend, the attack is confined to the origin of the configured S3 uploads hostname and cannot reach the Zulip server itself.","published":"2019-09-18T12:15:11.000Z","lastModified":"2026-06-17T02:21:55.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":5.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"},"cwe":["CWE-79"],"affected":["zulip/zulip server"],"epss":{"score":0.00681,"percentile":0.52256,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.68%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://github.com/zulip/zulip/commit/1195841dfb9aa26b3b0dabc6f05d72e4af25be3e","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/zulip/zulip/commit/1195841dfb9aa26b3b0dabc6f05d72e4af25be3e","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2019-16216","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}