How severe is CVE-2025-40908?

CVE-2025-40908 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2025-40908 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-40908?

CVE-2025-40908 affects Ingydotnet Yaml-libyaml. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-40908?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-40908 have an EU (EUVD) identifier?

Yes. CVE-2025-40908 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16577.

When was CVE-2025-40908 published?

CVE-2025-40908 was published on 2025-06-01 and last updated on 2026-06-17.

CVE-2025-40908

CVE-2025-40908 is a critical-severity vulnerability in Ingydotnet Yaml-libyaml with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-552.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-16577
Weakness: CWE-552
Affected product: Ingydotnet Yaml-libyaml
Published: 2025-06-01
Last modified: 2026-06-17

Description

YAML-LibYAML prior to 0.903.0 for Perl uses 2-args open, allowing existing files to be modified

Frequently asked questions

What is CVE-2025-40908?: YAML-LibYAML prior to 0.903.0 for Perl uses 2-args open, allowing existing files to be modified
How severe is CVE-2025-40908?: CVE-2025-40908 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2025-40908 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-40908?: CVE-2025-40908 affects Ingydotnet Yaml-libyaml. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-40908?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-40908 have an EU (EUVD) identifier?: Yes. CVE-2025-40908 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16577.
When was CVE-2025-40908 published?: CVE-2025-40908 was published on 2025-06-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ingydotnet:yaml-libyaml:*:*:*:*:*:perl:*:*

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