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Vulnerabilities / CVE-2026-50053

CVE-2026-50053

Published 2026-10-23 · published (not yet in NVD)

CVE-2026-50053

Zimbra Collaboration Suite RestFilter Request Attribute Override via Unauthenticated URL Parameters

8.7 HIGH
CVSS 3.1 · CNA
0.3%
chance of exploitation in the next 30 days (EPSS; higher than 22% of CVEs)

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.

Scores

8.7CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:NCNA

Affected products

  • Zimbra Zimbra Collaboration Suite: 0 to ≤ 10.1.17

Weakness: CWE-642

2 references (advisories, patches, write-ups)

Sources: CVE.org, FIRST EPSS. Missing ones did not answer or have no record yet.

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