Heap-Based Buffer Overflow in ncurses Package: CVE-2021-39537
Summary
ALPINE-CVE-2021-39537: An issue was discovered in ncurses through v6.2-1. _nc_captoinfo in captoinfo.c has a heap-based buffer overflow. Affects ncurses versions < 6.2_p20200523-r1. Fixed in 6.2_p20200523-r1. How to fix ↓
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Background
The ncurses package is a widely used library that provides functions to create text-based user interfaces in a terminal. It allows developers to manage multiple windows, handle keyboard input, and control the display of text in a terminal environment. This package is essential for applications that require a user-friendly interface in a command-line setting. However, it has been found to be vulnerable to a heap-based buffer overflow, which can lead to severe security issues.
Vulnerability Detail
An issue was discovered in ncurses through v6.2-1. The vulnerability, identified as CVE-2021-39537, is located in the _nc_captoinfo function within captoinfo.c. This flaw allows an attacker to exploit a heap-based buffer overflow, potentially leading to arbitrary code execution, data corruption, or crashes. The CVSS score for this vulnerability is 8.8, indicating a high severity level, which underscores the urgency for users to address this issue promptly.
How To Fix
Minimum fixed version
6.2_p20200523-r1
This is the first release that contains the fix.
sudo apk add --upgrade ncursesTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If immediate patching is not feasible, consider limiting access to the affected application or using alternative libraries that do not exhibit this vulnerability. Additionally, monitoring for unusual behavior in applications using ncurses can help mitigate potential exploitation.
Conclusion
The ncurses package is critical for creating text-based user interfaces, but it is currently vulnerable to a heap-based buffer overflow as identified in CVE-2021-39537. Users are strongly advised to update to the patched versions to mitigate the risks associated with this vulnerability. Additionally, utilizing tools like Vulert can help monitor and alert for such vulnerabilities in real-time.
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FAQ
CVE-2021-39537 is a vulnerability in the ncurses package that allows for a heap-based buffer overflow, potentially leading to arbitrary code execution.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Failure to fix this vulnerability can lead to severe security risks, including unauthorized access, data corruption, and application crashes.
Yes, you can limit access to the affected application and monitor for unusual behavior to reduce the risk of exploitation.
The CVSS score for CVE-2021-39537 is 8.8, indicating a high severity level.
References
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