What is the CVSS score of CVE-2024-45516?

CVE-2024-45516 has a CVSS 3.1 base score of 6.1 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N. EPSS exploitation probability: 0.3%.

How to fix or mitigate CVE-2024-45516?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Verify Content-Security-Policy and output encoding.

Zimbra Collaboration Suite CVE-2024-45516

MEDIUM

Cross-site Scripting (XSS) (CWE-79)

2025-05-14 cve@mitre.org

XSS Authentication Bypass Zimbra Collaboration Suite Synacor

6.1

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-79 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Output encoding, context-aware escaping MITRE ATT&CK 2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. EPSS exploitation probability: 0.29%.
Exploit ScenarioDerived	A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

An issue was discovered in Zimbra Collaboration (ZCS) 9.0.0 before Patch 43, 10.0.x before 10.0.12, 10.1.x before 10.1.4, and 8.8.15 before Patch 47. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. An issue was discovered in Zimbra Collaboration (ZCS) 9.0.0 before Patch 43, 10.0.x before 10.0.12, 10.1.x before 10.1.4, and 8.8.15 before Patch 47. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, including malformed <img> tags with embedded JavaScript. The vulnerability is triggered when a user views a specially crafted email in the Classic UI, requiring no additional user interaction. Affected products include: Synacor Zimbra Collaboration Suite. Version information: before 10.0.12.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.1 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

DescriptionCVE.org

An issue was discovered in Zimbra Collaboration (ZCS) 9.0.0 before Patch 43, 10.0.x before 10.0.12, 10.1.x before 10.1.4, and 8.8.15 before Patch 47. A Cross-Site Scripting (XSS) vulnerability in the Zimbra Classic UI allows attackers to execute arbitrary JavaScript within the user's session, potentially leading to unauthorized access to sensitive information. This issue arises from insufficient sanitization of HTML content, including malformed <img> tags with embedded JavaScript. The vulnerability is triggered when a user views a specially crafted email in the Classic UI, requiring no additional user interaction.

Executive ViewAI

Why It Matters

CVE-2024-45516 presents moderate security risk, a cross-site scripting vulnerability rated CVSS 6.1. Attackers could inject scripts to steal sessions or perform actions as authenticated users. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low

Compensating Controls

Apply vendor patch. If patching is delayed: implement CSP headers, enable HttpOnly cookies, deploy WAF XSS rules.

Threat Intelligence Overview

EPSS Score

0.3%

Top 48% exploitable

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC No

EPSS 0.3%

Patch available No

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Defer

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact

Low

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +30

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Cross-Site Scripting MEDIUM

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)CVE.org

cpe:2.3:a:synacor:zimbra_collaboration_suite:*:*:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:-:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p1:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p10:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p11:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p12:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p13:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p14:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p15:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p16:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p17:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p18:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p19:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p2:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p20:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p21:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p22:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p23:*:*:*:*:*:*

cpe:2.3:a:synacor:zimbra_collaboration_suite:8.8.15:p24:*:*:*:*:*:*

+ 74 more

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References

Advisories & patches

ADVISORY https://wiki.zimbra.com/wiki/Security_Center ADVISORY https://wiki.zimbra.com/wiki/Zimbra_Security_Advisories REF https://wiki.zimbra.com/wiki/Zimbra_Releases/10.1.4#Security_Fixes REF https://wiki.zimbra.com/wiki/Zimbra_Responsible_Disclosure_Policy

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