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CVE-2025-40908

27
FAUCET Score

CVE-2025-40908 is a critical vulnerability affecting ingydotnet yaml_libyaml, specifically Perl's YAML-LibYAML prior to version 0.903.0. The flaw stems from its use of a 2-argument open function, which allows an unauthenticated attacker to modify existing files remotely with low attack complexity. This vulnerability carries a CVSS score of 9.1 (CRITICAL), indicating high impact on confidentiality and integrity. Despite its severity, there is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.903.0CPE matchmatch criteria
cpe:2.3:a:ingydotnet:yaml-libyaml:*:*:*:*:*:perl:*:*

CVSS Data

CVSS version used by this source: 3.1

9.1CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.38%
Probability of exploitation in next 30 days
EPSS Percentile
31.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0038 is in the 8th percentile among its peer group of 36,862 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: perl-YAML-LibYAML-1:0.70-2.el8_10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: perl-YAML-LibYAML-1:0.82-6.1.el9_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 9.4 Extended Update SupportFixed in: perl-YAML-LibYAML-1:0.82-6.el9_4.1
View patch

Vendor Advisories (1)

redhatCVE-2025-40908Important

yaml-libyaml: LibYAML Perl File Modification Vulnerability

Jun 1, 2025

References

github.com / ingydotnet/yaml-libyaml-pm/issues/120
ExploitIssue Tracking
github.com / ingydotnet/yaml-libyaml-pm/pull/121
Issue TrackingPatch
github.com / ingydotnet/yaml-libyaml-pm/pull/122
Issue TrackingPatch