CVE-2026-50053highCWE-642

CVE-2026-50053: high-severity vulnerability in Zimbra Collaboration Suite

Zimbra Collaboration Suite RestFilter Request Attribute Override via Unauthenticated URL Parameters

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.7epss 0.3%
from disclosure to weapon6 days
Published on NVDOct 23
1st PoC+6d
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
Affected products
Zimbra · Zimbra Collaboration Suite
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