CISA description
Synacor Zimbra Collaboration Suite (ZCS) allows an attacker to upload arbitrary files using cpio package to gain incorrect access to any other user accounts.
Synacor · Zimbra Collaboration Suite (ZCS)
Synacor Zimbra Collaboration Suite (ZCS) Arbitrary File Upload Vulnerability
Synacor Zimbra Collaboration Suite (ZCS) allows an attacker to upload arbitrary files using cpio package to gain incorrect access to any other user accounts.
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Vulnerability data triggers these controls during assessment and continuous monitoring.