Denial of Service Vulnerability in libass: Out-of-Bounds Read Risk
Summary
ALPINE-CVE-2016-7969: The wrap_lines_smart function in ass_render.c in libass before 0.13.4 allows remote attackers to cause a denial of service (out-of-bounds read) via unspecified vectors, related to "0/3 line wrapping equalization.". Affects libass versions < 0.13.4-r0. Fixed in 0.13.4-r0. How to fix ↓
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Background
libass is a portable subtitle renderer that is widely used in multimedia applications to display subtitles in various formats. It is known for its high-quality rendering capabilities and support for advanced subtitle features. However, prior to version 0.13.4, libass contained a vulnerability that could allow remote attackers to exploit the library, leading to potential denial of service conditions.
Vulnerability Detail
The vulnerability, identified as CVE-2016-7969, resides in the wrap_lines_smart function within ass_render.c of libass versions prior to 0.13.4. It allows remote attackers to trigger an out-of-bounds read, which can lead to a denial of service. This issue arises from improper handling of line wrapping, specifically during the equalization of line wrapping conditions. Attackers can exploit this vulnerability through unspecified vectors, potentially causing applications that rely on libass to crash or behave unexpectedly.
How To Fix
Minimum fixed version
0.13.4-r0
This is the first release that contains the fix.
sudo apk add --upgrade libassTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If an immediate update is not feasible, consider disabling the use of libass in your application or restricting access to the functionality that utilizes this library until the update can be applied. Additionally, ensure that your application has proper input validation to mitigate potential exploitation.
Conclusion
CVE-2016-7969 represents a significant vulnerability in libass that can lead to denial of service through an out-of-bounds read. It is crucial for users and developers to update to the patched version to ensure the security and stability of their applications. Utilizing tools like Vulert can help monitor and alert for such vulnerabilities in real-time.
See every vulnerability recorded for libass →
FAQ
CVE-2016-7969 is a vulnerability in libass that allows remote attackers to cause a denial of service through an out-of-bounds read.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
Exploitation of this vulnerability can lead to application crashes or unexpected behavior, impacting user experience and system stability.
Yes, updating libass to version 0.13.4 or later will patch the vulnerability.
The CVSS score for CVE-2016-7969 is 7.5, indicating a high severity level.
References
Related vulnerabilities
Recent vulnerabilities recorded for libass.
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