CVE-2026-5778
Received Received - Intake
Integer Underflow in wolfSSL Packet Sniffer Causes Remote Crash

Publication date: 2026-04-09

Last updated on: 2026-04-29

Assigner: wolfSSL Inc.

Description
Integer underflow in wolfSSL packet sniffer <= 5.9.0 allows an attacker to cause a program crash 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 a large out-of-bounds read and crash. An unauthenticated attacker can trigger this remotely via malformed TLS Application Data records.
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Meta Information
Published
2026-04-09
Last Modified
2026-04-29
Generated
2026-06-16
AI Q&A
2026-04-10
EPSS Evaluated
2026-06-15
NVD
CVE-2026-5778
EUVD
EUVD-2026-21220
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
wolfssl wolfssl to 5.9.1 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
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.
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Executive Summary

This vulnerability is an integer underflow in the wolfSSL packet sniffer version 5.9.0 and earlier. It occurs in the AEAD decryption path when a TLS record shorter than the explicit IV plus authentication tag is injected into traffic inspected by the ssl_DecodePacket function. The underflow causes a 16-bit length value to wrap around to a large number, which is then passed to AEAD decryption routines. This results in a large out-of-bounds read and causes the program to crash.

An unauthenticated attacker can remotely trigger this vulnerability by sending malformed TLS Application Data records.

Impact Analysis

This vulnerability can cause a program crash in the affected wolfSSL packet sniffer during the AEAD decryption process. Since the crash is triggered by a large out-of-bounds read caused by an integer underflow, it may lead to denial of service conditions.

Because the attacker can trigger this remotely without authentication by sending malformed TLS records, it poses a risk of service disruption.

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