What’s Vulnerable › Vulnerabilities

CVE-2026-10632: Zimbra Collaboration Suite Classic Web Client Reflected Cross-Site Scripting via Document Editor Packages Parameter

• Severity: high (CVSS 8.7 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: 2026-10-23 · updated 2026-10-28
• Weakness: CWE-79

Description

A reflected cross-site scripting vulnerability in the Classic Web Client of Zimbra Collaboration Suite (ZCS) allows an attacker to inject JavaScript through the packages parameter of the /h/rest document editor. The editor inserts package names into script attributes without HTML encoding. When combined with CVE-2026-50053, an attacker with an ordinary Zimbra account can supply their own authentication token and document identifiers in a URL and execute JavaScript in another signed-in user's Zimbra browser session when that user opens the URL. This permits reading mailbox data and performing authenticated actions as the victim. The issue affects ZCS 10.1.16 and was remediated in 10.1.17.

Affected products

• Zimbra Collaboration: before 10.1.17 — fixed in 10.1.17

How to fix

Upgrade to a fixed version: Zimbra Collaboration 10.1.17. Check the vendor advisory for mitigations.

References

• https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
• https://www.rapid7.com/blog/post/ve-breaking-zimbra-identity-boundaries-part-1/

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