Multiple vulnerabilities in Zimbra Collaboration



Risk High
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2025-53645
CVE-2025-27915
CWE-ID CWE-20
CWE-79
Exploitation vector Network
Public exploit Vulnerability #2 is being exploited in the wild.
Vulnerable software
 Zimbra Collaboration
Web applications / Webmail solutions

Vendor Synacor Inc.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Input validation error

EUVDB-ID: #VU116622

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-53645

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper handling of excessive, comma-separated path segments in the Admin Console. A remote attacker can send specially crafted HTTP GET requests to the admin console and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Zimbra Collaboration: 9.0.0 - 10.1.8

CPE2.3 External links

https://wiki.zimbra.com/wiki/Security_Center#ZCS_9.0.0_Patch_46_Released
https://wiki.zimbra.com/wiki/Security_Center#ZCS_10.0.15_Released
https://wiki.zimbra.com/wiki/Security_Center#ZCS_10.1.9_Released


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Stored cross-site scripting

EUVDB-ID: #VU116623

Risk: High

CVSSv4.0: 6.4 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:A/U:Amber]

CVE-ID: CVE-2025-27915

CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Exploit availability: No

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to insufficient sanitization of user-supplied data when handling ICS files. A remote attacker can send an email message with a specially crafted calendar attachment and execute arbitrary JavaScript code in user's browser in context of vulnerable website.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

Note, the vulnerability is being actively exploited in the wild.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Zimbra Collaboration: 9.0.0 - 10.1.8

CPE2.3 External links

https://wiki.zimbra.com/wiki/Security_Center#ZCS_9.0.0_Patch_46_Released
https://wiki.zimbra.com/wiki/Security_Center#ZCS_10.0.15_Released
https://wiki.zimbra.com/wiki/Security_Center#ZCS_10.1.9_Released
https://strikeready.com/blog/0day-ics-attack-in-the-wild/


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.



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