wolfSSL up to 5.9.0 Compatibility Layer API wolfSSL_X509_notAfter/wolfSSL_X509_notBefore Date heap-based overflow

Summaryinfo

A vulnerability described as critical has been identified in wolfSSL up to 5.9.0. This affects the function wolfSSL_X509_notAfter/wolfSSL_X509_notBefore of the component Compatibility Layer API. The manipulation of the argument Date results in heap-based overflow. This vulnerability is known as CVE-2026-5448. Access to the local network is required for this attack. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical has been found in wolfSSL up to 5.9.0. Affected is the function wolfSSL_X509_notAfter/wolfSSL_X509_notBefore of the component Compatibility Layer API. The manipulation of the argument date with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on availability. CVE summarizes:

X.509 date buffer overflow in wolfSSL_X509_notAfter / wolfSSL_X509_notBefore. A buffer overflow may occur when parsing date fields from a crafted X.509 certificate via the compatibility layer API. This is only triggered when calling these two APIs directly from an application, and does not affect TLS or certificate verify operations in wolfSSL.

The weakness was published by Sunwoo Lee. The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-5448 since 04/02/2026. The exploitability is told to be easy. Access to the local network is required for this attack. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 305896 (Linux Distros Unpatched Vulnerability : CVE-2026-5448), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.9.1 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (305896). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

• wolfSSL

Version

• 5.0
• 5.1
• 5.2
• 5.3
• 5.4
• 5.5
• 5.6
• 5.7
• 5.8
• 5.9.0

License

• open-source

Website

• Product: https://github.com/wolfSSL/wolfssl/

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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