PatchTheCVECVE-2026-50053: A request attribute override vulnerability in Zimbra Collaboration Suite (ZCS) allows unauthenticated requests
CVE-2026-50053 is a high-severity flaw (CVSS 8.7) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 t
Why this priority
- High severity
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 8.7 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | Required |
| EPSS exploit chance | 0.4% (top 64%) |
| CISA exploited list | No |
| Weakness | CWE-642 |
| Published | 2026-10-23 |
| Last modified | 2026-10-23 |
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-50053?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-50053 being exploited?
CVE-2026-50053 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-50053 affect?
CVE-2026-50053 affects affected software. Severity is high (CVSS 8.7). 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 aut
How urgent is CVE-2026-50053?
Priority 39/100. High severity