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Vulnerabilities

Vulnerability · CVE-2026-4159

1-byte OOB heap read in wc_PKCS7_DecodeEnvelopedData via zero-length encrypted content.

Published Mar 19, 2026 · catalog updated Jun 17, 2026 · 1-byte OOB heap read

Check if you run it

No confirmed exploitation is on record for CVE-2026-4159. EPSS is 0.14%. Act only if a listed version of 1-byte OOB heap read is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (1-byte OOB heap read).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Low1.2
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.14%
Remediation
Version ranges on file
Affected products
cpe wolfssl/wolfssl · stated wolfssl

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe wolfssl/wolfsslversion unspecified
  • stated wolfssl<= 5.8.4

How to fix CVE-2026-4159

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-4159. EPSS is 0.14%. Act only if a listed version of 1-byte OOB heap read is installed.

Which versions are affected?

Compare what you have installed with <= 5.8.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-125: Out-of-bounds Read. EPSS 0.14%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 19, 2026 · NIST NVD

    Detected

    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.

  2. Jun 17, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2026-4159

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-4159

    30-day exploitation probability 0.1%

    first.org
  • NIST NVDVulnerability recordCVE-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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.