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CVE-2025-40908VulnerabilityPublished Updated

Red Hat Security Advisory: perl-YAML-LibYAML security update

Affects Red Hat perl-YAML-LibYAMLSource GCVE Database

0
Authoritative record:CVE-2025-40908· Critical 9.1

Not known to be exploited · CVSS 9.1 Critical : upgrade the Red Hat redhat/perl-YAML-LibYAML package to 9.4.1 as a priority.

Data as of 26 Oct 2026, 11:07 UTC

CVSS 3.1 base score
9.1Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 9.4.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 1 Jun 2025

  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

Upgrade the Red Hat redhat/perl-YAML-LibYAML package to 9.4.1.

Affected software

ProductAffectedFixed in
Red Hatredhat/perl-YAML-LibYAMLpkg:rpm/redhat/perl-YAML-LibYAMLOther threatsAffected
  • >=9.4 <9.4.1
Fixed in
  • 9.4.1

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

Description

Kirill Siminov's "libyaml" is arguably the best YAML implementation. The C library is written precisely to the YAML 1.1 specification. It was originally bound to Python and was later bound to Ruby. Security Fix(es): * yaml-libyaml: LibYAML Perl File Modification Vulnerability (CVE-2025-40908) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

References

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