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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.006 (46.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.006 · change: +0.002
Affected products
- Wolfssl — versions 0
Weakness classification (CWE)
References
- github.com/wolfSSL/wolfssl/pull/9988 (Patch, patch, Issue Tracking)
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.