Critical Security Update for libtasn1: Addressing Denial of Service Vulnerability
Summary
ALSA-2026:28235: Low: libtasn1 security update. Affects libtasn1 versions < 4.20.0-5.el10_2. Fixed in 4.20.0-5.el10_2. How to fix ↓
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Background
libtasn1 is a library that provides functionality for parsing and managing Abstract Syntax Notation One (ASN.1) structures, as well as encoding and decoding using Distinguished Encoding Rules (DER). It is widely used in various applications that require ASN.1 data handling. The library is crucial for ensuring proper data communication and security in network protocols and cryptographic systems. However, a recent vulnerability has been identified that could potentially compromise the integrity and availability of systems utilizing this library.
Vulnerability Detail
The vulnerability identified as CVE-2025-13151 is a Denial of Service (DoS) issue caused by a stack-based buffer overflow in the function asn1_expend_octet_string. This flaw can be exploited by an attacker to crash the application or service that relies on libtasn1, leading to service interruptions. The vulnerability arises from improper handling of input data, which can overflow the stack and disrupt normal operations. The impact of this vulnerability can be severe, especially in production environments where uptime is critical.
How To Fix
Minimum fixed version
4.20.0-5.el10_2
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, users may consider restricting access to applications that utilize libtasn1 until the package can be updated. Additionally, implementing input validation and sanitization can help mitigate the risk of exploitation until a proper fix is applied.
Conclusion
The libtasn1 library has a critical vulnerability that can lead to Denial of Service attacks. It is essential for users to update to the latest patched version to ensure the security and availability of their applications. Implementing workarounds can provide temporary relief, but a proper fix is necessary for long-term security.
See every vulnerability recorded for libtasn1 →
FAQ
CVE-2025-13151 is a vulnerability in the libtasn1 library that allows for a Denial of Service attack due to a stack-based buffer overflow.
You can check if your application is affected by using Vulert, which monitors open-source vulnerabilities in your software. Visit Vulert Scanner to test your application without any signup.
Exploitation of this vulnerability can lead to application crashes and service interruptions, affecting the availability of systems that rely on libtasn1.
Yes, a patch is available in version 4.20.0-5.el10_2 of the libtasn1 package. Updating to this version will resolve the vulnerability.
If immediate updates are not possible, consider implementing input validation and restricting access to the affected applications as a temporary measure.
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