wolfSSL up to 5.8.4 Authentication Tag ssl_DecodePacket integer underflow

Summaryinfo

A vulnerability identified as problematic has been detected in wolfSSL up to 5.8.4. The affected element is the function ssl_DecodePacket of the component Authentication Tag Handler. The manipulation leads to integer underflow. This vulnerability is documented as CVE-2026-1005. The attack can be initiated remotely. There is not any exploit available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in wolfSSL up to 5.8.4. This issue affects the function ssl_DecodePacket of the component Authentication Tag Handler. The manipulation with an unknown input leads to a integer underflow vulnerability. Using CWE to declare the problem leads to CWE-191. The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result. Impacted is availability. The summary by CVE is:

Integer underflow in wolfSSL packet sniffer <= 5.8.4 allows an attacker to cause a buffer overflow in the AEAD decryption path by injecting a TLS record shorter than the explicit IV plus authentication tag into traffic inspected by ssl_DecodePacket. The underflow wraps a 16-bit length to a large value that is passed to AEAD decryption routines, causing heap buffer overflow and a crash. An unauthenticated attacker can trigger this remotely via malformed TLS Application Data records.

The weakness was released by Prasanth Sundararajan. It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-1005 since 01/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 303269 (Linux Distros Unpatched Vulnerability : CVE-2026-1005), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the databases at Tenable (303269) and EUVD (EUVD-2026-13133). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• wolfSSL

Version

• 5.8.0
• 5.8.1
• 5.8.2
• 5.8.3
• 5.8.4

License

• open-source

Website

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

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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