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CVE-2026-4159VulnerabilityPublished Updated

Microsoft · wc_PKCS7_DecodeEnvelopedData 1 byte out-of-bounds read

Affects MicrosoftSource GCVE Database

0

Not known to be exploited.

Data as of 27 Oct 2026, 00:10 UTC

Severity
Medium

Rated Medium by Threat Radar's AI analysis · No CVSS score from NVD or the CNA

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 2 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
Microsoft Security Response Center MicrosoftAffected
  • =3.0
  • =2.0
Fixed in–

AI-suggested

Users should monitor official Microsoft advisories for updates and apply patches once released. Until then, no specific mitigation actions are documented.

Description

CVE-2026-4159 is a vulnerability involving a 1-byte out-of-bounds read in the wc_PKCS7_DecodeEnvelopedData function in Microsoft software versions 2.0 and 3.0. The vulnerability relates to improper memory access that could potentially lead to information disclosure or application instability.

References

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