What’s Vulnerable › Vulnerabilities

CVE-2025-52559: Zulip XSS in digest preview URL

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-07-02 · updated 2026-06-17
• Weakness: CWE-79

Description

Zulip is an open-source team chat application. From versions 2.0.0-rc1 to before 10.4 in Zulip Server, the /digest/ URL of a server shows a preview of what the email weekly digest would contain. This URL, though not the digest itself, contains a cross-site scripting (XSS) vulnerability in both topic names and channel names. This issue has been fixed in Zulip Server 10.4. A workaround for this issue involves denying access to /digest/.

Affected products

• zulip: from 2.0.1 before 10.4; 2.0.0-rc1 — fixed in 10.4

How to fix

Upgrade to a fixed version: zulip 10.4. Check the vendor advisory for mitigations.

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

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