Critical Heap Use-After-Free Vulnerability in Curl Package
Summary
ALPINE-CVE-2018-16840: A heap use-after-free flaw was found in curl versions from 7.59.0 through 7.61.1 in the code related to closing an easy handle. Affects curl versions < 7.62.0-r0. Fixed in 7.62.0-r0. How to fix ↓
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Background
Curl is a widely used command-line tool and library for transferring data with URLs. It supports various protocols including HTTP, HTTPS, FTP, and more, making it essential for web-related tasks. The library is known for its versatility and ease of use, but it is also susceptible to vulnerabilities that can compromise applications relying on it. This specific vulnerability affects multiple versions of Curl across various Alpine Linux distributions.
Vulnerability Detail
A heap use-after-free flaw was discovered in Curl versions from 7.59.0 through 7.61.1. This vulnerability arises in the Curl_close() function, where the library code frees a struct without nullifying the pointer. As a result, it may erroneously write to a field within the already freed struct, leading to potential memory corruption, crashes, or even arbitrary code execution. The severity of this vulnerability is underscored by its CVSS score of 9.8, indicating a critical risk to affected systems.
How To Fix
Minimum fixed version
7.62.0-r0
This is the first release that contains the fix.
sudo apk add --upgrade curlTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can avoid using the affected versions of Curl until they can upgrade to a patched version. Additionally, consider using alternative libraries for data transfer that do not have this vulnerability.
Conclusion
The heap use-after-free vulnerability in Curl poses a critical risk to applications using affected versions. It is essential for users to update to the patched version to mitigate potential security threats. Utilizing tools like Vulert can help in monitoring and managing vulnerabilities effectively.
See every vulnerability recorded for curl →
FAQ
A heap use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed. This can lead to unpredictable behavior, crashes, or security breaches.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. By uploading your manifest file, such as package-lock.json, you can check for vulnerabilities without needing to install any software.
Exploitation of this vulnerability can lead to memory corruption, application crashes, or even arbitrary code execution, which poses significant security risks to affected systems.
If immediate updates are not possible, consider using alternative libraries for data transfer or implementing strict memory management practices to reduce the risk of exploitation.
Detailed information about this vulnerability can be found in the CVE database and through security advisories related to Curl and Alpine Linux.
References
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