Request Attribute Override Vulnerability in Zimbra Collaboration Suite
CVE-2026-50053

8.7HIGH

Key Information:

Vendor

Zimbra

Status
Zimbra Collaboration Suite
Vendor
CVE Published:
23 October 2026

What is CVE-2026-50053?

A vulnerability in the Zimbra Collaboration Suite allows unauthenticated requests to manipulate servlet attributes intended for internal use. This flaw permits attackers to inject their own valid authentication tokens and identifiers, potentially executing JavaScript within an authenticated user's browser session. While version 10.1.17 implements measures to mitigate the risk by altering the document renderer, the core issue related to request attribute overriding remains a security concern.

Affected Version(s)

Zimbra Collaboration Suite 0 <= 10.1.17

References

https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
vendor-advisory
https://www.rapid7.com/blog/post/ve-breaking-zimbra-ident...
related

CVSS V3.1

Score:
8.7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Jonah Burgess (CryptoCat), Senior Security Researcher, Rapid7
.