CVE-2012-2138: Apache Sling POST Servlets Denial of Service Vulnerability
Summary
CVE-2012-2138: Apache Sling POST Servlets Denial of Service Vulnerability. Affects org.apache.sling:org.apache.sling.servlets.post versions < 2.1.2. Fixed in 2.1.2. How to fix ↓
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Background
The Apache Sling POST Servlets is a bundle in the Apache Sling framework that provides servlets for handling HTTP POST requests. It allows users to create, update, and delete resources in the Sling content repository. The POST servlet in the org.apache.sling.servlets.post bundle before version 2.1.2 is vulnerable to a denial of service attack.
Vulnerability Detail
The vulnerability, identified as CVE-2012-2138, exists in the @CopyFrom operation of the POST servlet. It fails to prevent attempts to copy an ancestor node to a descendant node. This flaw can be exploited by remote attackers to cause an infinite loop, resulting in a denial of service condition. By sending a crafted HTTP request, an attacker can trigger this vulnerability and disrupt the normal functioning of the affected Apache Sling instance.
How To Fix
Latest published version: 3.0.2 as of 22 Oct 2026
Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
2.1.2
This is the first release that contains the fix.
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Workaround
There is no known workaround for this vulnerability. It is essential to apply the recommended fix by updating the affected bundle to the latest version.
Conclusion
The Apache Sling POST Servlets bundle in Apache Sling is vulnerable to a denial of service attack due to a flaw in the @CopyFrom operation. To mitigate this vulnerability, it is crucial to update the affected bundle to version 2.1.2 or later. Users should apply the recommended fix as soon as possible to ensure the security and stability of their Apache Sling installations. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability allows remote attackers to cause a denial of service condition by triggering an infinite loop in the Apache Sling POST Servlets. This can lead to the unavailability of the affected service and disrupt normal operations.
You can use Vulert Playground (https://vulert.com/scanner) to check if your application is affected by this vulnerability. Vulert monitors and alerts in real-time for open-source vulnerabilities, using just the pom.xml file.
There are no known public exploits available for this vulnerability at the time of this report. However, it is recommended to apply the fix as soon as possible to prevent potential attacks.
Yes, a patch is available for this vulnerability. Users should update the org.apache.sling.servlets.post bundle to version 2.1.2 or later to fix the issue.
You can find more information about this vulnerability in the GitHub Advisory Database: [link to the vulnerability details in the GitHub Advisory Database].
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