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CVE-2026-4395— Heap-based buffer overflow in wc_ecc_import_x963_ex KCAPI path

Quick assessment

Affected
wolfSSL wolfssl
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

wolfSSL（CyaSSL）是美国wolfSSL公司的一个针对嵌入式系统开发人员使用的小的、可移植的嵌入式SSL编程库。 wolfSSL存在安全漏洞，该漏洞源于wc_ecc_import_x963_ex的KCAPI ECC代码路径中存在基于堆的缓冲区溢出，特制的超长EC公钥点可能导致攻击者控制的数据写入pubkey_raw缓冲区边界之外。

AI Predicted 8.1 Difficulty: Hard EPSS 0.59% · P46

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application
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I. Basic Information for CVE-2026-4395

Vulnerability Information
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Vulnerability Title
Heap-based buffer overflow in wc_ecc_import_x963_ex KCAPI path
Source: CVE Program / CVE List V5
Vulnerability Description
Heap-based buffer overflow in the KCAPI ECC code path of wc_ecc_import_x963_ex() in wolfSSL wolfcrypt allows a remote attacker to write attacker-controlled data past the bounds of the pubkey_raw buffer via a crafted oversized EC public key point. The WOLFSSL_KCAPI_ECC code path copies the input to key->pubkey_raw (132 bytes) using XMEMCPY without a bounds check, unlike the ATECC code path which includes a length validation. This can be triggered during TLS key exchange when a malicious peer sends a crafted ECPoint in ServerKeyExchange.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/AU:Y/R:U/V:D/RE:L/U:Amber
Source: CVE Program / CVE List V5
Vulnerability Type
堆缓冲区溢出
Source: CVE Program / CVE List V5
Vulnerability Title
wolfSSL 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
wolfSSL（CyaSSL）是美国wolfSSL公司的一个针对嵌入式系统开发人员使用的小的、可移植的嵌入式SSL编程库。 wolfSSL存在安全漏洞，该漏洞源于wc_ecc_import_x963_ex的KCAPI ECC代码路径中存在基于堆的缓冲区溢出，特制的超长EC公钥点可能导致攻击者控制的数据写入pubkey_raw缓冲区边界之外。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
wolfSSL wolfssl 0 ~ 5.8.4 -

II. Public POCs for CVE-2026-4395

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III. Intelligence Information for CVE-2026-4395

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Patches & Fixes for CVE-2026-4395 (1)

Same Patch Batch · wolfSSL · 2026-03-19 · 11 CVEs total

CVE-2026-3547 7.5 HIGH wolfSSL: out-of-bounds read (DoS) in ALPN parsing due to incomplete validation
CVE-2026-0819 Stack buffer overflow in PKCS7 SignedData encoding with custom signed attributes
CVE-2026-1005 Integer underflow leads to out-of-bounds access in sniffer AES-GCM/CCM/ARIA-GCM decrypt pa
CVE-2026-2646 Heap buffer overflow in session parsing with wolfSSL_d2i_SSL_SESSION() function
CVE-2026-2645 Acceptance of CertificateVerify Message before ClientKeyExchange in TLS 1.2
CVE-2026-3548 Buffer overflow in CRL number parsing in wolfSSL
CVE-2026-3579 Non-constant time multiplication subroutine __muldi3 on RISC-V RV32I
CVE-2026-3580 Compiler-induced timing leak in sp_256_get_entry_256_9 on RISC-V
CVE-2026-3230 Improper key_share validation in TLS 1.3 HelloRetryRequest
CVE-2026-4159 wc_PKCS7_DecodeEnvelopedData 1 byte out-of-bounds read

IV. Related Vulnerabilities

Same product: wolfssl
Same vendor: wolfSSL
Same weakness: CWE-122

V. Comments for CVE-2026-4395

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