XSS in Zulip Server
CVE-2019-16216
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.
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.007 (48.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
Affected products
- Zulip Zulip_server
- N/a — versions n/a
Weakness classification (CWE)
References
- cve@mitre.org (x_refsource_CONFIRM, Vendor Advisory)
- cve@mitre.org (x_refsource_CONFIRM, Patch, Third Party Advisory)
Frequently asked questions
- What is CVE-2019-16216?
- CVE-2019-16216 is a medium-severity vulnerability in Zulip Server, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2019-09-18.
- How severe is CVE-2019-16216?
- Medium severity. CVSS v3 base score is 5.4 out of 10.