How severe is CVE-2026-4395?

CVE-2026-4395 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-4395 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4395?

CVE-2026-4395 affects Wolfssl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4395?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-4395 have an EU (EUVD) identifier?

Yes. CVE-2026-4395 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13235.

When was CVE-2026-4395 published?

CVE-2026-4395 was published on 2026-03-19 and last updated on 2026-06-17.

CVE-2026-4395

CVE-2026-4395 is a critical-severity vulnerability in Wolfssl with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 1.3
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13235
Weakness: CWE-122
Affected product: Wolfssl
Published: 2026-03-19
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2026-4395?: CVE-2026-4395 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-4395 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4395?: CVE-2026-4395 affects Wolfssl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4395?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-4395 have an EU (EUVD) identifier?: Yes. CVE-2026-4395 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13235.
When was CVE-2026-4395 published?: CVE-2026-4395 was published on 2026-03-19 and last updated on 2026-06-17.

References

https://github.com/wolfSSL/wolfssl/pull/9988

Affected products (1)

cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*

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