CVE-2011-4462: Plone Hash Collision Denial of Service
Summary
CVE-2011-4462: Plone 4.1.3 and earlier computes hash values for form parameters without restricting the ability to trigger hash collisions predictably, which allows remote attackers to cause a denial of service (CPU consumption) by sen... Affects plone versions < 4.1.4. Fixed in 4.1.4. How to fix ↓
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Background
Plone is an open-source content management system built on top of the Zope application server. It provides a user-friendly interface for managing websites and supports various features such as content creation, collaboration, and workflow management. Plone is widely used in both small and large organizations for building robust and secure web applications.
Vulnerability Detail
Plone versions 4.1.3 and earlier suffer from a vulnerability that allows remote attackers to cause a denial of service (CPU consumption) by sending many crafted parameters. The issue lies in the way Plone computes hash values for form parameters without properly restricting the ability to trigger hash collisions predictably. By exploiting this vulnerability, an attacker can overwhelm the server's CPU resources, leading to a significant degradation in performance or even a complete service outage.
How To Fix
Latest published version: 6.2.2 as of 23 Oct 2026
pip install --upgrade "plone==6.2.2"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
4.1.4
This is the first release that contains the fix.
pip install --upgrade "plone==4.1.4"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
There is no known workaround for this vulnerability. It is essential to apply the official patch or upgrade to a fixed version as soon as possible.
Conclusion
The Plone Hash Collision Denial of Service vulnerability in versions 4.1.3 and earlier can be exploited by remote attackers to cause a denial of service by overwhelming the server's CPU resources. To mitigate this risk, it is recommended to upgrade to Plone version 4.1.4 or later. Alternatively, you can use the Vulert Playground at https://vulert.com/scanner to check if your Plone installation is affected and take appropriate actions. For further assistance or support in vulnerability remediation, please contact DevNack.com.
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FAQ
The vulnerability allows remote attackers to consume excessive CPU resources, leading to a denial of service. This can result in degraded performance or a complete service outage.
You can use the Vulert Playground at Vulert Scanner to check if your Plone installation is affected by this vulnerability. Simply provide your Pipfile.lock, and Vulert will analyze it for any known vulnerabilities.
At the time of this advisory, there are no known public exploits targeting this specific vulnerability. However, it is crucial to apply the recommended fixes to mitigate any potential risks.
Yes, this vulnerability can be exploited remotely. Attackers can send crafted parameters to the Plone server, triggering hash collisions and causing a denial of service.
There is no evidence of active exploitation of this vulnerability at the time of this advisory. However, it is still important to apply the necessary patches or upgrades to ensure the security of your Plone installation.
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