CVE-2017-18342

CRITICALNVD 9.89.8
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 6%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In PyYAML before 5.1, the yaml.load() API could execute arbitrary code if used with untrusted data. The load() function has been deprecated in version 5.1 and the 'UnsafeLoader' has been introduced for backward compatibility with the function.

CVSS v3
9.8
EG Score
9.8(low)
EPSS
92.5%
KEV
Not listed

Published

June 27, 2018

Last Modified

November 21, 2024

Advisory Details (9)

Auto-updated Jul 6, 2026
Patch available. Sources: github_pr.
generic

Use 'yaml.safe_load' in 'load_yaml_from_docstring' · Issue #278 · marshmallow-code/apispec · GitHub

https://github.com/marshmallow-code/apispec/issues/278
generic

PyYAML: Arbitrary code execution (GLSA 202003-45) — Gentoo security

https://security.gentoo.org/glsa/202003-45
generic

[SECURITY] Fedora 29 Update: PyYAML-5.1-1.fc29 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M6JCFGEIEOFMWWIXGHSELMKQDD4CV2BA/
generic

[SECURITY] Fedora 28 Update: PyYAML-5.1-1.fc28 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/KSQQMRUQSXBSUXLCRD3TSZYQ7SEZRKCE/
generic

[SECURITY] Fedora 30 Update: PyYAML-5.1-1.fc30 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JEX7IPV5P2QJITAMA5Z63GQCZA5I6NVZ/
generic

PyYAML yaml.load(input) Deprecation · yaml/pyyaml Wiki · GitHub

https://github.com/yaml/pyyaml/wiki/PyYAML-yaml.load%28input%29-Deprecation
github_pr Patch Available

Make pyyaml safe by default.

Patch available: yaml/pyyaml 6.0.2rc1 (PR #74 merged 2017-08-26)

https://github.com/yaml/pyyaml/pull/74
generic

PyYAML 4.2 Release Plan · Issue #193 · yaml/pyyaml · GitHub

https://github.com/yaml/pyyaml/issues/193
generic

pyyaml/CHANGES at main · yaml/pyyaml · GitHub

https://github.com/yaml/pyyaml/blob/master/CHANGES

Vendor Advisories for CVE-2017-18342(1)

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

Affected Packages

(1 across 1 ecosystem)
PyPI(1)
PackageVulnerable rangeFixed inDependents
pyyaml3.01 ... 5.1b7 (22 versions)5.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× 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.

  1. 2026-07-11 08:24 UTCEPSS rescore
  2. 2026-07-09 19:06 UTCEPSS rescore
  3. 2026-07-08 15:10 UTCEPSS rescore
  4. 2026-07-07 13:42 UTCEPSS rescore
  5. 2026-07-06 16:24 UTCEPSS rescore
  6. 2026-07-06 16:24 UTCEPSS rescore
  7. 2026-07-06 02:20 UTCEPSS rescore
  8. 2026-07-06 02:20 UTCEPSS rescore
  9. 2026-07-05 02:27 UTCEPSS rescore
  10. 2026-07-04 06:28 UTCEPSS rescore
  11. 2026-07-02 16:54 UTCEPSS rescore
  12. 2026-07-01 15:02 UTCEPSS rescore
  13. 2026-06-30 23:19 UTCEPSS rescore
  14. 2026-06-30 23:19 UTCEPSS rescore
  15. 2026-06-29 14:03 UTCEPSS rescore
  16. 2026-06-28 04:53 UTCEPSS rescore
  17. 2026-06-27 03:06 UTCEPSS rescore
  18. 2026-06-27 03:05 UTCEPSS rescore
  19. 2026-06-25 13:47 UTCEPSS rescore
  20. 2026-06-24 14:02 UTCEPSS rescore
  21. 2026-06-24 14:02 UTCEPSS rescore
  22. 2026-06-24 03:59 UTCOSV refresh
  23. 2026-06-23 21:30 UTCEPSS rescore
  24. 2026-06-22 14:23 UTCEPSS rescore
  25. 2026-06-22 14:23 UTCEPSS rescore
Show 44 more
  1. 2026-06-21 14:54 UTCEPSS rescore
  2. 2026-06-21 14:54 UTCEPSS rescore
  3. 2026-06-21 01:57 UTCEPSS rescore
  4. 2026-06-21 01:57 UTCEPSS rescore
  5. 2026-06-19 19:23 UTCEPSS rescore
  6. 2026-06-19 19:23 UTCEPSS rescore
  7. 2026-06-18 17:50 UTCEPSS rescore
  8. 2026-06-17 17:50 UTCEPSS rescore
  9. 2026-06-16 17:50 UTCEPSS rescore
  10. 2026-06-16 17:50 UTCEPSS rescore
  11. 2026-06-15 17:45 UTCEPSS rescore
  12. 2026-06-14 23:14 UTCEPSS rescore
  13. 2026-06-13 22:57 UTCEPSS rescore
  14. 2026-06-12 23:09 UTCEPSS rescore
  15. 2026-06-10 22:15 UTCEPSS rescore
  16. 2026-06-10 13:19 UTCEPSS rescore
  17. 2026-06-08 14:14 UTCEPSS rescore
  18. 2026-06-08 14:14 UTCEPSS rescore
  19. 2026-06-07 15:22 UTCEPSS rescore
  20. 2026-06-07 15:22 UTCEPSS rescore
  21. 2026-06-07 08:50 UTCOSV refresh
  22. 2026-06-06 13:45 UTCEPSS rescore
  23. 2026-06-06 13:45 UTCEPSS rescore
  24. 2026-06-05 22:44 UTCEPSS rescore
  25. 2026-06-05 06:08 UTCEPSS rescore
  26. 2026-06-05 06:08 UTCEPSS rescore
  27. 2026-06-04 13:10 UTCEPSS rescore
  28. 2026-06-02 20:11 UTCEPSS rescore
  29. 2026-06-02 20:11 UTCEPSS rescore
  30. 2026-06-01 13:49 UTCEPSS rescore
  31. 2026-05-31 22:28 UTCEPSS rescore
  32. 2026-05-31 22:28 UTCEPSS rescore
  33. 2026-05-31 00:14 UTCEPSS rescore
  34. 2026-05-31 00:14 UTCEPSS rescore
  35. 2026-05-29 13:41 UTCEPSS rescore
  36. 2026-05-28 13:42 UTCEPSS rescore
  37. 2026-05-28 13:42 UTCEPSS rescore
  38. 2026-05-27 13:38 UTCEPSS rescore
  39. 2026-05-27 13:38 UTCEPSS rescore
  40. 2026-05-26 13:42 UTCEPSS rescore
  41. 2026-05-26 13:42 UTCEPSS rescore
  42. 2026-05-26 07:17 UTCEPSS rescore
  43. 2026-05-26 07:17 UTCEPSS rescore
  44. 2026-05-23 02:29 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2017-18342?
CVE-2017-18342 is a critical vulnerability published on June 27, 2018. In PyYAML before 5.1, the yaml.load() API could execute arbitrary code if used with untrusted data. The load() function has been deprecated in version 5.1 and the 'UnsafeLoader' has been introduced for backward compatibility with the function.
When was CVE-2017-18342 disclosed?
CVE-2017-18342 was first published in the National Vulnerability Database on June 27, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2017-18342 actively exploited?
CVE-2017-18342 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 92.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2017-18342?
CVE-2017-18342 has a CVSS v3 base score of 9.8 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2017-18342?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2017-18342, 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.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2017-18342

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