CVE-2025-40908

CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence

Score 9.1 from GitHub Security Advisory (severity: CRITICAL) published 2025-06-01. NVD baseline CVSS 9.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
9.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.1Exploit: None knownExposed: 0

A fix is available — apply it.

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

CVSS v3
9.1
EG Score
9.1(medium)
EG Risk
56(Track)
EG Risk 56/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity91% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
33%
KEV
Not listed

Published

June 1, 2025

Last Modified

July 2, 2025

Advisory Details (3)

Auto-updated Aug 1, 2026
Upstream fix merged — awaiting tagged release. Sources: github_pr.
github_pr

regression test for GH#120. 3args open.

Upstream fix in progress (PR #122 · ingydotnet/yaml-libyaml-pm, state=open)

https://github.com/ingydotnet/yaml-libyaml-pm/pull/122
github_pr

Use 3-arg form of open in LoadFile

Fix merged in ingydotnet/yaml-libyaml-pm PR #121 on 2025-02-02 — awaiting tagged release

https://github.com/ingydotnet/yaml-libyaml-pm/pull/121
generic

"LoadFile" uses 2-args open, allowing to truncate existing files · Issue #120 · ingydotnet/yaml-libyaml-pm · GitHub

https://github.com/ingydotnet/yaml-libyaml-pm/issues/120

Vendor Advisories for CVE-2025-40908(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulibyaml-libyaml-perl (0.89+ds-1ubuntu0.24.04.1) @ noble2026-05-30ubuntu
redhatperl-YAML-LibYAML-1:0.82-6.el9_4.12025-06-23redhat
redhatperl-YAML-LibYAML-1:0.70-2.el8_102025-06-23redhat
redhatperl-YAML-LibYAML-1:0.82-6.1.el9_62025-06-23redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 6× in last 7d / 39× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 102 total refreshes for this CVE.

  1. 2026-08-07 16:26 UTCEPSS rescore
  2. 2026-08-06 13:46 UTCEPSS rescore
  3. 2026-08-04 15:09 UTCEPSS rescore
  4. 2026-08-04 10:37 UTCEPSS rescore
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  15. 2026-07-24 04:41 UTCOSV refresh
  16. 2026-07-23 02:55 UTCEG score recompute
  17. 2026-07-22 14:07 UTCEPSS rescore
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  1. 2026-07-18 10:04 UTCEPSS rescore
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  13. 2026-07-09 19:09 UTCEPSS rescore
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  15. 2026-07-07 00:21 UTCOSV refresh
  16. 2026-07-06 16:27 UTCEPSS rescore
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  23. 2026-06-30 23:22 UTCEPSS rescore
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  25. 2026-06-28 14:07 UTCEPSS rescore
  26. 2026-06-28 14:07 UTCEPSS rescore
  27. 2026-06-28 04:55 UTCEPSS rescore
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  37. 2026-06-22 14:25 UTCEPSS rescore
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  39. 2026-06-21 14:56 UTCEPSS rescore
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  41. 2026-06-21 01:59 UTCEPSS rescore
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  43. 2026-06-19 19:25 UTCEPSS rescore
  44. 2026-06-19 19:25 UTCEPSS rescore
  45. 2026-06-18 17:52 UTCEPSS rescore
  46. 2026-06-18 17:52 UTCEPSS rescore
  47. 2026-06-18 11:13 UTCOSV refresh
  48. 2026-06-17 17:52 UTCEPSS rescore
  49. 2026-06-16 17:52 UTCEPSS rescore
  50. 2026-06-16 17:52 UTCEPSS rescore
  51. 2026-06-14 23:17 UTCEPSS rescore
  52. 2026-06-13 23:00 UTCEPSS rescore
  53. 2026-06-12 23:11 UTCEPSS rescore
  54. 2026-06-11 14:00 UTCEPSS rescore
  55. 2026-06-10 22:18 UTCEPSS rescore
  56. 2026-06-10 13:22 UTCEPSS rescore
  57. 2026-06-08 14:16 UTCEPSS rescore
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  59. 2026-06-07 15:24 UTCEPSS rescore
  60. 2026-06-06 13:47 UTCEPSS rescore
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  62. 2026-06-05 22:46 UTCEPSS rescore
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  66. 2026-06-04 13:12 UTCEPSS rescore
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  68. 2026-06-02 20:12 UTCEPSS rescore
  69. 2026-06-01 13:51 UTCEPSS rescore
  70. 2026-06-01 13:51 UTCEPSS rescore
  71. 2026-05-31 22:30 UTCEPSS rescore
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  73. 2026-05-31 00:16 UTCEPSS rescore
  74. 2026-05-30 04:27 UTCEG score recompute
  75. 2026-05-30 04:27 UTCVendor advisory

Frequently asked(5)

What is CVE-2025-40908?
CVE-2025-40908 is a critical vulnerability published on June 1, 2025. YAML-LibYAML prior to 0.903.0 for Perl uses 2-args open, allowing existing files to be modified
When was CVE-2025-40908 disclosed?
CVE-2025-40908 was first published in the National Vulnerability Database on June 1, 2025, with the most recent update on July 2, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-40908 actively exploited?
CVE-2025-40908 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 67.2% of all scored CVEs.
What is the CVSS score of CVE-2025-40908?
CVE-2025-40908 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2025-40908?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-40908, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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