Cve20207796 Zimbra Collaboration Suite Full !free! Site

CVE-2020-7796 is a critical Server-Side Request Forgery (SSRF) vulnerability in the Synacor Zimbra Collaboration Suite (ZCS) that allows unauthenticated remote attackers to force the server to send HTTP requests to arbitrary internal or external destinations. Rated with a CVSS score of 9.8, this flaw recently gained renewed attention after being added to CISA's Known Exploited Vulnerabilities (KEV) Catalog in February 2026 due to active exploitation in the wild. Technical Overview

The vulnerability stems from insufficient validation of user-supplied URLs within the WebEx Zimlet (com_zimbra_webex) component.

Conditions: The flaw is present when the WebEx Zimlet is installed and its associated Jakarta Server Pages (JSP) functionality is enabled.

Mechanism: An unauthenticated attacker can send a specially crafted HTTP request to the vulnerable Zimlet. Because the server does not properly sanitize the input, it treats the server itself as a proxy, executing requests on behalf of the attacker. Impact and Risks

Successful exploitation allows attackers to bypass traditional network defenses like firewalls and gain access to restricted internal services. Key risks include:

Internal Reconnaissance: Attackers can map internal networks and identify other vulnerable services for further attacks.

Data Exfiltration: Sensitive information residing on the internal network, which is otherwise inaccessible from the public internet, can be leaked.

Attack Chaining: The SSRF can be used as a stepping stone to chain with other exploits, potentially leading to Remote Code Execution (RCE) or full system compromise. Current Threat Landscape

Despite being originally identified in 2020, CVE-2020-7796 has seen a massive resurgence in activity. Security researchers observed a significant spike in exploitation attempts in early 2026, with nearly 400 distinct IP addresses targeting the flaw globally. This surge prompted CISA to mandate federal agencies to apply fixes by March 10, 2026. Remediation and Mitigation CVE-2020-7796 Detail - NVD

CVE-2020-7796: Zimbra Collaboration Suite Vulnerability Exposes Millions of Users to Cyber Threats

The Zimbra Collaboration Suite, a popular open-source email and collaboration platform, has been vulnerable to a critical security flaw, known as CVE-2020-7796. This vulnerability affects the full suite, exposing millions of users worldwide to potential cyber threats. In this article, we will explore the details of the vulnerability, its impact, and the necessary steps to mitigate the risks.

What is Zimbra Collaboration Suite?

Zimbra Collaboration Suite is a comprehensive email and collaboration platform designed for businesses and organizations. It offers a range of features, including email, calendar, contacts, and file sharing, making it a popular choice for enterprises seeking to streamline their communication and collaboration needs. The suite is available in both open-source and commercial editions, with the open-source version being widely used by organizations worldwide. cve20207796 zimbra collaboration suite full

What is CVE-2020-7796?

CVE-2020-7796 is a critical vulnerability in the Zimbra Collaboration Suite, which allows an attacker to inject arbitrary JavaScript code into the application. The vulnerability exists due to inadequate input validation in the Zimbra web application, specifically in the handling of autocomplete results. This flaw enables an attacker to craft a malicious request that injects JavaScript code, potentially leading to the theft of sensitive user data, session hijacking, or other malicious activities.

Impact of CVE-2020-7796

The impact of CVE-2020-7796 is significant, as it can be exploited by an attacker to gain unauthorized access to sensitive user data, including email content, contacts, and other personal information. The vulnerability affects all versions of Zimbra Collaboration Suite prior to 8.8.15 Patch 7 and 9.0.0 Patch 4. This means that millions of users worldwide, including those using the open-source edition, are potentially exposed to cyber threats.

Exploitation of CVE-2020-7796

The exploitation of CVE-2020-7796 is relatively straightforward. An attacker can craft a malicious request that injects JavaScript code into the Zimbra application. This code can then be executed by the victim's browser, allowing the attacker to steal sensitive user data or perform other malicious actions. The vulnerability can be exploited via a phishing email or by visiting a malicious website.

Mitigation and Patching

To mitigate the risks associated with CVE-2020-7796, Zimbra has released patches for affected versions of the Collaboration Suite. Users can upgrade to version 8.8.15 Patch 7 or 9.0.0 Patch 4 to fix the vulnerability. Additionally, administrators can implement several security measures to reduce the risk of exploitation:

  1. Disable autocomplete: Disable autocomplete functionality in the Zimbra web application to prevent the exploitation of the vulnerability.
  2. Implement a web application firewall: Use a web application firewall (WAF) to detect and block malicious requests.
  3. Monitor user activity: Monitor user activity and logs to detect potential security incidents.
  4. Educate users: Educate users about the risks associated with CVE-2020-7796 and the importance of being cautious when clicking on links or providing sensitive information.

Conclusion

CVE-2020-7796 is a critical vulnerability in the Zimbra Collaboration Suite that exposes millions of users worldwide to potential cyber threats. The vulnerability can be exploited by an attacker to inject arbitrary JavaScript code into the application, leading to the theft of sensitive user data or other malicious activities. To mitigate the risks, users should upgrade to patched versions of the Collaboration Suite and implement additional security measures, such as disabling autocomplete, implementing a WAF, monitoring user activity, and educating users about the risks associated with the vulnerability.

Recommendations

  • Upgrade to version 8.8.15 Patch 7 or 9.0.0 Patch 4 to fix the vulnerability.
  • Implement a web application firewall to detect and block malicious requests.
  • Monitor user activity and logs to detect potential security incidents.
  • Educate users about the risks associated with CVE-2020-7796 and the importance of being cautious when clicking on links or providing sensitive information.

References

By taking the necessary steps to mitigate the risks associated with CVE-2020-7796, organizations can protect their users and prevent potential cyber threats.

CVE-2020-7796 is a critical Server-Side Request Forgery (SSRF) vulnerability in the Zimbra Collaboration Suite (ZCS). It allows unauthenticated remote attackers to force the server to make HTTP requests to arbitrary internal or external hosts by abusing the server as a proxy. Vulnerability Overview Vulnerability Type: Server-Side Request Forgery (SSRF).

Severity: Ranked as Critical with a CVSS v3.1 base score of 9.8/10.

Affected Versions: All versions of Zimbra Collaboration Suite (ZCS) prior to 8.8.15 Patch 7.

Root Cause: Insufficient validation of user-supplied URLs within the WebEx zimlet component, specifically when zimlet JSP (Jakarta Server Pages) is enabled. Impact and Exploitation

Unauthorized Access: Attackers can bypass firewalls to access sensitive internal resources or metadata services.

Data Leakage: Successful exploitation can lead to the exposure of sensitive configuration and application data.

Active Exploitation: This flaw is included in the CISA Known Exploited Vulnerabilities (KEV) Catalog, meaning it has been actively exploited in the wild.

Malware Risks: Threat actors have been observed using this flaw to download malware, such as the Dogkild worm, which can disable security processes and alter system files. Remediation and Mitigations

To secure your environment, the following actions are recommended by security researchers and official Zimbra documentation:

Primary Fix: Upgrade to Zimbra Collaboration Suite 8.8.15 Patch 7 or higher. Alternative Mitigations:

Disable the WebEx Zimlet: Since the flaw resides in this specific component, disabling it or its JSP functionality can block the attack vector. Conclusion CVE-2020-7796 is a critical vulnerability in the

Network Controls: Restrict outbound connections from the Zimbra server to only necessary external destinations to prevent the server from being used as a proxy for malicious requests.

Monitor Traffic: Scan for atypical file inclusion requests and unauthorized access patterns in server logs.

Further technical details and patch instructions can be found on the NVD Detail Page and the Red Hat Customer Portal. CVE-2020-7796 Detail - NVD

Conclusion

CVE-2020-27996 is a classic but powerful reflected XSS flaw in Zimbra Collaboration Suite, made severe due to Zimbra’s complex routing and proxy architecture. While its CVSS score is “Medium,” its real-world impact — especially when combined with CVE-2020-27995 — is full system compromise. Administrators must patch immediately or apply strict URL filtering to prevent exploitation.

Final recommendation: Always keep Zimbra Collaboration Suite updated. Subscribe to Zimbra’s security announcements and perform regular security audits of custom integrations and exposed servlets.

Last updated: 2026-04-19
References: NVD, Zimbra Security Advisories, Rapid7 Analysis, Project Discovery research.

2.3 Root Cause Analysis

The core issue is tied to the handling of RAR archives. Historically, the unrar binary used by Zimbra was a statically linked binary maintained by the vendor or relied upon from upstream repositories that were outdated. The vulnerability allows the attacker to escape the constraints of the scanning process and execute commands as the zimbra user, and subsequently escalate privileges to root due to default configuration permissions.

What makes it "Full" RCE?

Unlike many vulnerabilities that yield limited access (e.g., file read only, or authenticated RCE), CVE-2020-27996 allows an unauthenticated remote attacker to execute arbitrary system commands with the privileges of the Zimbra service user (typically zimbra). This is the equivalent of handing over the keys to the kingdom.

Attack Vector and Exploitation

The exploitation of this vulnerability is relatively straightforward, making it a prime target for threat actors. The attack chain typically proceeds as follows:

  1. Crafting the Payload: An attacker creates a malicious payload, usually a Java Server Page (.jsp) web shell, which allows the execution of system commands on the server.
  2. The Upload Request: The attacker sends a specifically crafted HTTP POST request to the vulnerable Zimbra endpoint (/service/admin/soap). The request targets the MboxImportRequest method.
  3. Path Traversal & Placement: By manipulating the upload parameters (specifically using path traversal sequences or taking advantage of how the server unpacks archives), the attacker forces the server to write the malicious .jsp file into a directory that is executable by the web server (usually within the jetty webapps directory).
  4. Execution: Once the file is uploaded, the attacker can access the malicious .jsp file via a standard web browser. This executes the code within the file, granting the attacker a shell on the underlying Linux operating system.

CVE-2020-27996: Full Technical Analysis of the Zimbra Collaboration Suite Vulnerability

2.1 Vulnerability Description

The vulnerability exists within the unrar utility bundled with ZCS. Zimbra uses Amavis to scan email attachments for viruses and spam. Amavis calls external binaries, including unrar, to process archived files (specifically .rar files).

The specific flaw is a buffer overflow vulnerability. The version of unrar included in ZCS did not properly validate the length of user-supplied data before copying it into a fixed-length memory buffer. By crafting a malicious RAR archive with specially designed metadata or content, an attacker can trigger the buffer overflow, overwrite memory, and execute arbitrary shellcode.