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Known Exploited Vulnerability
5.4
MEDIUM CVSS 3.1
CVE-2025-27915
Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability - [Actively Exploited]
Description

An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.

INFO

Published Date :

March 12, 2025, 3:15 p.m.

Last Modified :

Oct. 21, 2025, 11:16 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

Synacor Zimbra Collaboration Suite (ZCS) contains a cross-site scripting vulnerability that exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.

Required Action :

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Notes :

https://wiki.zimbra.com/wiki/Security_Center ; https://nvd.nist.gov/vuln/detail/CVE-2025-27915

Affected Products

The following products are affected by CVE-2025-27915 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Zimbra collaboration
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
Sanitize HTML content in ICS files to prevent stored XSS attacks.
  • Sanitize HTML content in ICS files.
  • Update affected Zimbra Collaboration versions.
  • Validate user input for ICS processing.
  • Avoid rendering untrusted HTML directly.
Public PoC/Exploit Available at Github

CVE-2025-27915 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-27915.

URL Resource
https://wiki.zimbra.com/wiki/Security_Center Release Notes
https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_Fixes Release Notes
https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_Fixes Release Notes
https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_Fixes Release Notes
https://strikeready.com/blog/0day-ics-attack-in-the-wild/ Exploit Third Party Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-27915 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-27915 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
maldua-pimbra/maldua-pimbra

Main repo about patched Zimbra repos

Updated: 3 months, 3 weeks ago
3 stars 0 fork 0 watcher
Born at : March 20, 2025, 1 p.m. This repo has been linked 1 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-27915 vulnerability anywhere in the article.

  • Daily CyberSecurity
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Published Date: Oct 30, 2025 (21 hours, 56 minutes ago)
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Jenkins Faces Wave of Plugin Flaws, Including SAML Authentication Bypass (CVE-2025-64131)

The Jenkins project has issued a major security advisory addressing a wave of vulnerabilities, including high-severity flaws that threaten the integrity and confidentiality of automation servers world ... Read more

Published Date: Oct 30, 2025 (22 hours, 26 minutes ago)
  • Daily CyberSecurity
ISC Patches High-Severity Kea DHCPv4 DoS (CVE-2025-11232) Flaw, Allows Crash via Malformed Hostname

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Published Date: Oct 30, 2025 (22 hours, 39 minutes ago)
  • Daily CyberSecurity
Wordfence Warns of Active Exploits Targeting Critical Privilege Escalation Flaw in WP Freeio (CVE-2025-11533)

The Wordfence Threat Intelligence team has issued an urgent warning about CVE-2025-11533, a critical privilege escalation vulnerability (CVSS 9.8) in the WP Freeio plugin, a component of the premium F ... Read more

Published Date: Oct 30, 2025 (22 hours, 46 minutes ago)
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Researcher Details Critical Authentication Bypasses in WSO2 API Manager and Identity Server

Security researcher Crnkovic has disclosed three critical vulnerabilities — CVE-2025-9152, CVE-2025-10611, and CVE-2025-9804 — in WSO2 API Manager and WSO2 Identity Server, each scoring 9.8 on the CVS ... Read more

Published Date: Oct 30, 2025 (23 hours, 44 minutes ago)
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TEE.fail: Researchers Break Intel SGX/TDX and AMD SEV-SNP with Sub-$1,000 DDR5 Memory Bus Attack

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Published Date: Oct 30, 2025 (23 hours, 51 minutes ago)
  • Daily CyberSecurity
Researcher Details Windows Cloud Files Mini Filter Driver Elevation of Privilege Flaw (CVE-2025-55680)

Researchers from Exodus Intelligence, led by Michele Campa, have disclosed a privilege-escalation vulnerability in Microsoft’s Cloud Files Minifilter driver (cldflt.sys) that affects all versions of W ... Read more

Published Date: Oct 30, 2025 (1 day ago)
  • Daily CyberSecurity
LiteSpeed Cache Flaw (CVE-2025-12450): 7 Million WordPress Sites Exposed to XSS Attack

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Published Date: Oct 29, 2025 (1 day, 13 hours ago)
  • Daily CyberSecurity
CISA KEV Alert: Critical DELMIA Apriso Flaws Under Active Exploitation Allow RCE and Privileged Access

The Cybersecurity and Infrastructure Security Agency (CISA) has added two critical Dassault Systèmes DELMIA Apriso vulnerabilities to its Known Exploited Vulnerabilities (KEV) Catalog, following confi ... Read more

Published Date: Oct 29, 2025 (1 day, 20 hours ago)
  • Daily CyberSecurity
Critical IBM Maximo Flaw (CVE-2025-36386, CVSS 9.8) Allows Unauthenticated Bypass to Cognos Analytics

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Published Date: Oct 29, 2025 (1 day, 20 hours ago)
  • Daily CyberSecurity
Docker Compose Path Traversal (CVE-2025-62725) Allows Arbitrary File Overwrite via OCI Artifacts

The Docker Compose project has disclosed a high-severity path traversal vulnerability tracked as CVE-2025-62725 (CVSS v4 8.9), which affects users across Docker Desktop, standalone Compose binaries, C ... Read more

Published Date: Oct 29, 2025 (2 days ago)
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Wear OS Messages Flaw (CVE-2025-12080) Allows Unprivileged Apps to Send SMS/RCS Without Permission, PoC Available

Security researcher Gabriele Digregorio has disclosed a newly identified vulnerability in Google Messages for Wear OS, designated CVE-2025-12080 (CVSS v4 6.9), that allows any installed app to send SM ... Read more

Published Date: Oct 29, 2025 (2 days ago)
  • Daily CyberSecurity
Critical Magento Flaw (CVE-2025-54236) Actively Exploited for Session Hijacking and Unauthenticated RCE

The Akamai Security Intelligence Group has issued an urgent warning after observing active exploitation in the wild of a newly disclosed Magento vulnerability known as SessionReaper (CVE-2025-54236). ... Read more

Published Date: Oct 29, 2025 (2 days ago)
  • Daily CyberSecurity
Critical MikroTik Flaw (CVE-2025-61481, CVSS 10.0) Exposes Router Admin Credentials Over Unencrypted HTTP WebFig

A newly disclosed vulnerability, CVE-2025-61481, rated a maximum CVSS score of 10.0, affects MikroTik RouterOS (v7.14.2) and SwitchOS (v2.18) and allows remote attackers to execute arbitrary code or i ... Read more

Published Date: Oct 29, 2025 (2 days ago)
  • Daily CyberSecurity
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Earlier, Microsoft released a security update to address a critical vulnerability in ASP.NET, identified as CVE-2025-55315 with a CVSS score of 9.8. At the time, the .NET team noted that the actual se ... Read more

Published Date: Oct 28, 2025 (2 days, 20 hours ago)
  • Daily CyberSecurity
Microsoft Teams Will Auto-Track Office Location via Wi-Fi

Microsoft’s collaborative workspace platform Microsoft Teams, widely used by enterprises and professional teams, is set to receive a notable new feature this December, according to the latest roadmap ... Read more

Published Date: Oct 28, 2025 (2 days, 20 hours ago)
  • Daily CyberSecurity
Values Over Cash: Python Foundation Rejects $1.5M US Grant Over Anti-DEI Clause

In January 2025, the Python Software Foundation (PSF) submitted a proposal to the U.S. National Science Foundation (NSF) under the Open Source Ecosystem Security, Safety, and Privacy initiative, aimin ... Read more

Published Date: Oct 28, 2025 (2 days, 20 hours ago)
  • Daily CyberSecurity
Kaspersky Exposes Chrome Zero-Day RCE (CVE-2025-2783) Delivering Memento Labs Spyware in ForumTroll Campaign

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Published Date: Oct 28, 2025 (2 days, 21 hours ago)
  • Daily CyberSecurity
High-Severity OpenVPN Flaw (CVE-2025-10680) Allows Script Injection on Linux/macOS via Malicious DNS Server

Security researchers have disclosed a high-severity vulnerability, tracked as CVE-2025-10680 (CVSS 8.8), affecting OpenVPN 2.7_alpha1 through 2.7_beta1 releases. The flaw exposes Unix-like systems to ... Read more

Published Date: Oct 28, 2025 (2 days, 21 hours ago)
  • Daily CyberSecurity
SideWinder APT Shifts to PDF/ClickOnce Chain to Target South Asian Diplomacy with StealerBot

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Published Date: Oct 28, 2025 (2 days, 22 hours ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-27915 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Removed Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27915
  • Modified Analysis by [email protected]

    Oct. 08, 2025

    Action Type Old Value New Value
    Added Reference Type CISA-ADP: https://strikeready.com/blog/0day-ics-attack-in-the-wild/ Types: Exploit, Third Party Advisory
  • CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725

    Oct. 08, 2025

    Action Type Old Value New Value
    Added Date Added 2025-10-07
    Added Due Date 2025-10-28
    Added Required Action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
    Added Vulnerability Name Synacor Zimbra Collaboration Suite (ZCS) Cross-site Scripting Vulnerability
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 07, 2025

    Action Type Old Value New Value
    Added Reference https://strikeready.com/blog/0day-ics-attack-in-the-wild/
  • Initial Analysis by [email protected]

    Apr. 02, 2025

    Action Type Old Value New Value
    Added CPE Configuration OR *cpe:2.3:a:zimbra:collaboration:9.0.0:-:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p2:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p3:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p4:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p5:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p6:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p9:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p0:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p1:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p10:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p11:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p12:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p13:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p14:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p15:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p19:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p7:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p8:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p16:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p20:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p21:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p23:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p24:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p24.1:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p25:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p26:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p27:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p28:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p29:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p30:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p31:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p32:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p33:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p34:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p35:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p36:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p37:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p38:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p39:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p40:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p7.1:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:*:*:*:*:*:*:*:* versions from (including) 10.0.0 up to (excluding) 10.0.13 *cpe:2.3:a:zimbra:collaboration:9.0.0:p41:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p42:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:9.0.0:p43:*:*:*:*:*:* *cpe:2.3:a:zimbra:collaboration:*:*:*:*:*:*:*:* versions from (including) 10.1.0 up to (excluding) 10.1.5
    Added Reference Type MITRE: https://wiki.zimbra.com/wiki/Security_Center Types: Release Notes
    Added Reference Type MITRE: https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_Fixes Types: Release Notes
    Added Reference Type MITRE: https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_Fixes Types: Release Notes
    Added Reference Type MITRE: https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_Fixes Types: Release Notes
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Mar. 12, 2025

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    Added CWE CWE-79
  • New CVE Received by [email protected]

    Mar. 12, 2025

    Action Type Old Value New Value
    Added Description An issue was discovered in Zimbra Collaboration (ZCS) 9.0 and 10.0 and 10.1. A stored cross-site scripting (XSS) vulnerability exists in the Classic Web Client due to insufficient sanitization of HTML content in ICS files. When a user views an e-mail message containing a malicious ICS entry, its embedded JavaScript executes via an ontoggle event inside a <details> tag. This allows an attacker to run arbitrary JavaScript within the victim's session, potentially leading to unauthorized actions such as setting e-mail filters to redirect messages to an attacker-controlled address. As a result, an attacker can perform unauthorized actions on the victim's account, including e-mail redirection and data exfiltration.
    Added Reference https://wiki.zimbra.com/wiki/Security_Center
    Added Reference https://wiki.zimbra.com/wiki/Zimbra_Releases/10.0.13#Security_Fixes
    Added Reference https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.5#Security_Fixes
    Added Reference https://wiki.zimbra.com/wiki/Zimbra_Releases/9.0.0/P44#Security_Fixes
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.4
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact