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CVE-2026-4177VulnerabilityPublished Updated

Microsoft · YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity

Affects MicrosoftSource GCVE Database

0
Authoritative record:CVE-2026-4177· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical.

Data as of 28 Oct 2026, 09:43 UTC

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 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
TODDRYAML::SyckAffected
  • <=1.36
Fixed in–
GitHubYAML-Syckpkg:github/YAML-SyckOther threatsAffected
  • <=1.36
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

CVE-2026-4177 affects YAML::Syck versions through 1.36 for Perl and involves several potential security vulnerabilities, including at least one high-severity issue. The specific technical details and impact are not provided. No CVSS score or detailed vendor advisory is available. The affected version explicitly stated is version 3.0 of a Microsoft product related to this vulnerability.

References

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