SB2018041816 - Multiple vulnerabilities in Zulip Server

Description

This security bulletin contains information about 4 secuirty vulnerabilities.

1) Cross-site scripting (CVE-ID: CVE-2018-9999)

Vulnerability allows a remote attacker to perform XSS attacks.

The vulnerability is caused by an input validation error related to user uploads and the (default) LOCAL_UPLOADS_DIR storage backend. A remote attacker can create a specially specially crafted web page, trick the victim intop opening it and execute arbitrary HTML and script code in victim's browser.

2) Cross-site scripting (CVE-ID: CVE-2018-9990)

Vulnerability allows a remote attacker to perform XSS attacks.

The vulnerability is caused by an input validation error related to stream names in topic typeahead. A remote attacker can create a specially specially crafted web page, trick the victim intop opening it and execute arbitrary HTML and script code in victim's browser.

3) Cross-site scripting (CVE-ID: CVE-2018-9987)

Vulnerability allows a remote attacker to perform XSS attacks.

The vulnerability is caused by an input validation error related to muting notifications. A remote attacker can create a specially specially crafted web page, trick the victim intop opening it and execute arbitrary HTML and script code in victim's browser.

4) Cross-site scripting (CVE-ID: CVE-2018-9986)

Vulnerability allows a remote attacker to perform XSS attacks.

The vulnerability is caused by an input validation error related to the frontend markdown processor. A remote attacker can create a specially specially crafted web page, trick the victim intop opening it and execute arbitrary HTML and script code in victim's browser.

Remediation

Install update from vendor's website.

References

• https://blog.zulip.org/2018/04/12/zulip-1-7-2-released/