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.



Source: MITRE

Published: 2019-09-18

Updated: 2019-09-18

Type: CWE-79

Risk Information

CVSS v2.0

Base Score: 3.5

Vector: AV:N/AC:M/Au:S/C:N/I:P/A:N

Impact Score: 2.9

Exploitability Score: 6.8

Severity: LOW