Microsoft · YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity
Affects MicrosoftSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 28 Oct 2026, 09:43 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| TODDRYAML::Syck | Affected
| Fixed in– |
GitHubYAML-Syckpkg:github/YAML-SyckOther threats | Affected
| 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.