How severe is CVE-2026-4159?

CVE-2026-4159 has a CVSS 3.x base score of 3.3, rated low severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-4159 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-4159?

CVE-2026-4159 affects Wolfssl. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-4159?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-4159 have an EU (EUVD) identifier?

Yes. CVE-2026-4159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13233.

When was CVE-2026-4159 published?

CVE-2026-4159 was published on 2026-03-19 and last updated on 2026-06-17.

CVE-2026-4159

CVE-2026-4159 is a low-severity vulnerability in Wolfssl with a CVSS 3.x base score of 3.3. 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-125.

Key facts

Severity: Low (CVSS 3.x base score 3.3)
CVSS v4: 1.2
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13233
Weakness: CWE-125
Affected product: Wolfssl
Published: 2026-03-19
Last modified: 2026-06-17

Description

1-byte OOB heap read in wc_PKCS7_DecodeEnvelopedData via zero-length encrypted content. A vulnerability existed in wolfSSL 5.8.4 and earlier, where a 1-byte out-of-bounds heap read in wc_PKCS7_DecodeEnvelopedData could be triggered by a crafted CMS EnvelopedData message with zero-length encrypted content. Note that PKCS7 support is disabled by default.

Frequently asked questions

What is CVE-2026-4159?: 1-byte OOB heap read in wc_PKCS7_DecodeEnvelopedData via zero-length encrypted content. A vulnerability existed in wolfSSL 5.8.4 and earlier, where a 1-byte out-of-bounds heap read in wc_PKCS7_DecodeEnvelopedData could be triggered by a crafted CMS EnvelopedData message with zero-length encrypted content. Note that PKCS7 support is disabled by default.
How severe is CVE-2026-4159?: CVE-2026-4159 has a CVSS 3.x base score of 3.3, rated low severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-4159 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-4159?: CVE-2026-4159 affects Wolfssl. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-4159?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-4159 have an EU (EUVD) identifier?: Yes. CVE-2026-4159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13233.
When was CVE-2026-4159 published?: CVE-2026-4159 was published on 2026-03-19 and last updated on 2026-06-17.

References

https://github.com/wolfSSL/wolfssl/pull/9945

Affected products (1)

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

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