CVE-2026-50053 Zimbra Collaboration Suite RestFilter Request Attribute Override via Unauthenticated URL Parameters
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-50053?
CVE-2026-50053 is a high-severity vulnerability in Zimbra Collaboration Suite, published on 23 Oct 2026.
Official description
A request attribute override vulnerability in Zimbra Collaboration Suite (ZCS) allows unauthenticated requests to /h/* to populate servlet attributes intended for trusted internal dispatch. RestFilter copies URL parameters specifying an authentication token, target account, target item and dispatch state into the request attributes consumed by the Classic Web Client. Combined with CVE-2026-10632 on ZCS 10.1.16, this allows an attacker to supply their own valid token and document identifiers and execute JavaScript in another user's signed-in browser session. ZCS 10.1.17 blocks that XSS chain by changing the document renderer, but retains the request attribute override.
Weakness: CWE-642
Which versions are affected by CVE-2026-50053?
How do I fix CVE-2026-50053?
No fix has been published for CVE-2026-50053 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-50053 being exploited?
There is no known exploitation of CVE-2026-50053 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-vffh-47xc-pr68.