SB20250716105 - Cross-site scripting in Zulip Server

Description

This security bulletin contains information about 1 security vulnerability.

1) Cross-site scripting (CVE-ID: CVE-2025-52559)

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data in digest preview URL. A remote user can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Remediation

Install update from vendor's website.

References

• https://github.com/zulip/zulip/commit/175ec1f365b0db982d6eac9019701cbf6e8bc2f2
• https://github.com/zulip/zulip/commit/1a8429e338ff53bdcc4b42e7e71b6fffdd84fcd1
• https://github.com/zulip/zulip/commit/6608c8777254e73a4b540e5e1c4af92e680a55fc
• https://github.com/zulip/zulip/security/advisories/GHSA-vgf2-vw4r-m663