CVE-2026-5460
Received Received - Intake
Use-After-Free in wolfSSL TLS 1.3 PQC Hybrid KeyShare Processing

Publication date: 2026-04-10

Last updated on: 2026-04-29

Assigner: wolfSSL Inc.

Description
A heap use-after-free exists in wolfSSL's TLS 1.3 post-quantum cryptography (PQC) hybrid KeyShare processing. In the error handling path of TLSX_KeyShare_ProcessPqcHybridClient() in src/tls.c, the inner function TLSX_KeyShare_ProcessPqcClient_ex() frees a KyberKey object upon encountering an error. The caller then invokes TLSX_KeyShare_FreeAll(), which attempts to call ForceZero() on the already-freed KyberKey, resulting in writes of zero bytes over freed heap memory.
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Meta Information
Published
2026-04-10
Last Modified
2026-04-29
Generated
2026-06-16
AI Q&A
2026-04-10
EPSS Evaluated
2026-06-14
NVD
CVE-2026-5460
EUVD
EUVD-2026-21240
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
wolfssl wolfssl to 5.9.1 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-416 The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
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Executive Summary

This vulnerability is a heap use-after-free issue in wolfSSL's TLS 1.3 post-quantum cryptography (PQC) hybrid KeyShare processing. Specifically, when an error occurs in the function TLSX_KeyShare_ProcessPqcHybridClient(), an inner function frees a KyberKey object. However, the caller then tries to operate on this already-freed object by calling ForceZero(), which writes zero bytes over freed heap memory, leading to potential memory corruption.

Impact Analysis

The use-after-free vulnerability can lead to memory corruption, which may be exploited by attackers to cause crashes, execute arbitrary code, or compromise the security of the TLS 1.3 PQC hybrid key exchange process in wolfSSL. This undermines the confidentiality and integrity of secure communications relying on this library.

Mitigation Strategies

To mitigate this vulnerability, you should update the wolfSSL library to version 5.9.1 or later, which includes the fix for CVE-2026-5460.

The fix addresses pointer sanity issues in the Post-Quantum Cryptography hybrid KeyShare implementation, preventing memory corruption and security vulnerabilities.

Applying this update will enhance the robustness and security of wolfSSL’s PQC hybrid key exchange mechanism.

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