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CVE-2026-50053EUVD-2026-108962GHSA-VFFH-47XC-PR68

Zimbra Collaboration Suite RestFilter Request Attribute Override via Unauthenticated URL Parameters

Published
Last modified
published
Not listed in CISA KEV
1 proof of concept on GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

Zimbra Collaboration Suite (ZCS), a widely used email and collaboration platform, is affected. An unauthenticated attacker can manipulate request parameters to override internal settings, and when combined with a second flaw, this could let them run malicious scripts in another user's signed-in browser session.

Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.

Read the original 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.

Timeline

  1. CVE published
  2. First seen by cve.now
  3. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  4. Record last updated

Affected versions

  • Zimbra Zimbra Collaboration Suite

    through 10.1.17

References 3

wiki.zimbra.com

rapid7.com

GitHub · mehmet-emir-eroglu/CVE-2026-50053