Buffer overflow in Wolfssl

CVE-2026-4395

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.

Vulnerability class: Buffer Overflow

EPSS: 0.003 (27.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-4395?
CVE-2026-4395 is a critical-severity vulnerability in Wolfssl, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2026-03-19.
How severe is CVE-2026-4395?
Critical severity. CVSS v3 base score is 9.8 out of 10.