Unauthorized EWS actions via content-type validation bypass
Published Aug 13, 2026 · Updated Aug 13, 2026
Cross-site request forgery in Zimbra Collaboration before 10.1.17 allows remote attackers to perform unauthorized EWS actions. The EWS endpoint accepts crafted requests because it insufficiently validates their content types and processes them with an authenticated browser session. Exploitation requires an authenticated user to be induced to submit the request, and the resulting action runs with that user's authority.
Summary
What happened
Cross-site request forgery in Zimbra Collaboration before 10.1.17 allows remote attackers to perform unauthorized EWS actions. The EWS endpoint accepts crafted requests because it insufficiently validates their content types and processes them with an authenticated browser session. Exploitation requires an authenticated user to be induced to submit the request, and the resulting action runs with that user's authority.
The record
- CVE
- CVE-2026-73575
- Published
- Aug 13, 2026
- Updated
- Aug 13, 2026
- Vendor
- Zimbra
- Product
- Zimbra Collaboration
- Classifications
- CWE-352, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 13, 2026CVE publishedPublication date reported by the CVE source.
- Aug 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <10.1.17
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo