Critical severity · published Jul 2, 2021
CVE-2021-35209
An issue was discovered in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.x before 9.0.0 Patch 16
9.8
CVSS
3%
EPSS
No
On KEV
Description
An issue was discovered in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.x before 9.0.0 Patch 16. The value of the X-Host header overwrites the value of the Host header in proxied requests. The value of X-Host header is not checked against the whitelist of hosts Zimbra is allowed to proxy to (the zimbraProxyAllowedDomains setting).
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.0% · higher than 87% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CO
Collaboration · Zimbra
8.8 before 8.8.15; 8.8.15; 8.8.15; 8.8.15; 8.8.15; 8.8.15; +28 more · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-35209
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-35209
Exploit
https://blog.sonarsource.com/zimbra-webmail-compromise-via-email
Release Notes
https://wiki.zimbra.com/wiki/Security_Center
Release Notes
https://wiki.zimbra.com/wiki/Zimbra_Releases/8.8.15/P23
Release Notes
https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P16
Vendor Advisory
https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories
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