High severity · published Oct 8, 2026
CVE-2026-50054
Zimbra Collaboration Suite GrantRightsRequest SOAP Handler Allows Self-Granting of Undocumented loginAs Mailbox Delegation Right
7.1
CVSS
0.2%
EPSS
No
On KEV
Description
An authorization flaw in Zimbra Collaboration Suite’s GrantRightsRequest allows an attacker with access to an authenticated account to grant another local account the loginAs right, creating persistent mailbox access and mail-sending authority that survives password changes and session expiry.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 6% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
Collaboration · Zimbra
before 10.1.20 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-50054
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-50054
vendor-advisory
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
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