EUVD-2026-21240
GHSA-w87p-fqgx-cqq8
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
3Description
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.
Analysis
Heap use-after-free in wolfSSL's TLS 1.3 post-quantum cryptography hybrid KeyShare processing allows unauthenticated remote attackers to corrupt heap memory and potentially disclose information. The vulnerability occurs when TLSX_KeyShare_ProcessPqcHybridClient() error handling prematurely frees a KyberKey object in src/tls.c, and the caller's subsequent TLSX_KeyShare_FreeAll() invocation writes zero bytes to already-freed memory. …
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External POC / Exploit Code
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