Critical Security Update for libtasn1: Denial of Service Vulnerability
Summary
ALSA-2026:36728: Low: libtasn1 security update. Affects libtasn1 versions < 4.13-6.el8_10. Fixed in 4.13-6.el8_10. How to fix ↓
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Background
libtasn1 is a library that provides functionalities for parsing Abstract Syntax Notation One (ASN.1) and managing structures, as well as encoding and decoding using Distinguished Encoding Rules (DER). It is widely used in various applications for handling data structures in a standardized format. However, it has been identified to have a vulnerability that could lead to a Denial of Service (DoS) attack, affecting the stability and availability of applications relying on this library.
Vulnerability Detail
The vulnerability identified as CVE-2025-13151 is a stack-based buffer overflow in the function asn1_expend_octet_string within libtasn1. This flaw can be exploited by an attacker to cause a Denial of Service, potentially crashing the application or making it unresponsive. The vulnerability arises from improper handling of input data, which can lead to excessive memory usage and stack overflow, thereby compromising the application's integrity and availability.
How To Fix
Minimum fixed version
4.13-6.el8_10
This is the first release that contains the fix.
sudo dnf update libtasn1Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, you can limit the input size to the asn1_expend_octet_string function to prevent the overflow. However, this is not a permanent solution and updating the package is strongly recommended.
Conclusion
The libtasn1 library has a critical vulnerability that can lead to Denial of Service attacks. It is crucial to update to the latest patched version to ensure the security and stability of applications using this library. Regular monitoring for vulnerabilities using tools like Vulert can help maintain the integrity of your software.
See every vulnerability recorded for libtasn1 →
FAQ
CVE-2025-13151 is a security vulnerability in libtasn1 that allows for a Denial of Service attack due to a stack-based buffer overflow.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected without any signup.
The vulnerability can lead to application crashes or unresponsiveness, affecting the availability and stability of services relying on libtasn1.
Yes, a patch is available in version 4.13-6.el8_10 of libtasn1 and its related packages.
If immediate updates are not possible, consider implementing input size limitations as a temporary workaround until you can apply the patch.
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