CVE-2020-8166

MEDIUMNVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under NVD CVSS v3. EPSS exploit probability: 1.7%, top 26% of all CVEs by exploit prediction. 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: epss, nvd
Elevated
4.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 2%CVSS: 4.3Exploit: Elevated riskExposed: 0

A fix is available — apply it.

A CSRF forgery vulnerability exists in rails < 5.2.5, rails < 6.0.4 that makes it possible for an attacker to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token.

CVSS v3
4.3
EG Score
4.3(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: 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
Severity43% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
2%
EPSS %ILE
76%
KEV
Not listed

Published

July 2, 2020

Last Modified

April 28, 2026

References (7)

Vendor Advisories for CVE-2020-8166(1)

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

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhattfm-rubygem-zeitwerk-0:2.2.2-1.el7sat2021-04-21redhat

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.

Affected Packages

(6 across 6 ecosystems)
Debian:10(1)
PackageVulnerable rangeFixed inDependents
rails2:5.2.2.1+dfsg-1, 2:5.2.2.1+dfsg-1+deb10u12:5.2.2.1+dfsg-1+deb10u2—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
rails—2:5.2.4.3+dfsg-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
rails—2:5.2.4.3+dfsg-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
rails—2:5.2.4.3+dfsg-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
rails—2:5.2.4.3+dfsg-1—
RubyGems(1)
PackageVulnerable rangeFixed inDependents
actionpack6.0.0 ... 6.0.3.rc1 (10 versions)6.0.3.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 23× 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 196 total refreshes for this CVE.

  1. 2026-09-18 19:23 UTCEPSS rescore
  2. 2026-09-18 01:50 UTCOSV refresh
  3. 2026-09-17 19:22 UTCEPSS rescore
  4. 2026-09-16 14:04 UTCEPSS rescore
  5. 2026-09-15 03:06 UTCEPSS rescore
  6. 2026-09-13 16:43 UTCEPSS rescore
  7. 2026-09-12 14:57 UTCEPSS rescore
  8. 2026-09-08 21:56 UTCEPSS rescore
  9. 2026-09-07 15:58 UTCEPSS rescore
  10. 2026-09-06 13:44 UTCEPSS rescore
  11. 2026-09-05 15:25 UTCEPSS rescore
  12. 2026-09-04 13:57 UTCEPSS rescore
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  14. 2026-09-04 05:03 UTCEPSS rescore
  15. 2026-09-02 14:08 UTCEPSS rescore
  16. 2026-09-01 03:32 UTCEPSS rescore
  17. 2026-08-30 19:14 UTCEPSS rescore
  18. 2026-08-30 02:43 UTCOSV refresh
  19. 2026-08-30 01:19 UTCEPSS rescore
  20. 2026-08-28 21:37 UTCEPSS rescore
  21. 2026-08-27 14:21 UTCEPSS rescore
  22. 2026-08-26 14:42 UTCEPSS rescore
  23. 2026-08-21 23:45 UTCEPSS rescore
  24. 2026-08-19 17:00 UTCEPSS rescore
  25. 2026-08-18 13:44 UTCEPSS rescore
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  1. 2026-08-17 13:43 UTCEPSS rescore
  2. 2026-08-17 13:43 UTCEPSS rescore
  3. 2026-08-16 14:52 UTCEPSS rescore
  4. 2026-08-16 02:11 UTCEPSS rescore
  5. 2026-08-15 01:27 UTCEPSS rescore
  6. 2026-08-13 21:57 UTCEPSS rescore
  7. 2026-08-13 13:51 UTCOSV refresh
  8. 2026-08-12 13:47 UTCEPSS rescore
  9. 2026-08-09 13:43 UTCEPSS rescore
  10. 2026-08-08 16:33 UTCEPSS rescore
  11. 2026-08-07 16:23 UTCEPSS rescore
  12. 2026-08-06 13:43 UTCEPSS rescore
  13. 2026-08-05 19:14 UTCEPSS rescore
  14. 2026-08-04 15:06 UTCEPSS rescore
  15. 2026-08-04 10:34 UTCEPSS rescore
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  17. 2026-08-01 04:12 UTCEPSS rescore
  18. 2026-07-30 16:25 UTCEPSS rescore
  19. 2026-07-30 01:27 UTCEPSS rescore
  20. 2026-07-28 20:47 UTCOSV refresh
  21. 2026-07-28 15:33 UTCEPSS rescore
  22. 2026-07-26 14:52 UTCEPSS rescore
  23. 2026-07-25 14:15 UTCEPSS rescore
  24. 2026-07-24 14:15 UTCEPSS rescore
  25. 2026-07-23 14:15 UTCEPSS rescore
  26. 2026-07-23 01:55 UTCEG score recompute
  27. 2026-07-22 22:41 UTCEG score recompute
  28. 2026-07-22 14:05 UTCEPSS rescore
  29. 2026-07-21 15:22 UTCEPSS rescore
  30. 2026-07-21 15:22 UTCEPSS rescore
  31. 2026-07-20 17:04 UTCEPSS rescore
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  33. 2026-07-19 14:28 UTCEPSS rescore
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  37. 2026-07-18 10:02 UTCEPSS rescore
  38. 2026-07-16 17:00 UTCEPSS rescore
  39. 2026-07-15 16:55 UTCEPSS rescore
  40. 2026-07-15 16:55 UTCEPSS rescore
  41. 2026-07-15 01:57 UTCEPSS rescore
  42. 2026-07-13 22:27 UTCEPSS rescore
  43. 2026-07-13 22:27 UTCEPSS rescore
  44. 2026-07-13 06:10 UTCEPSS rescore
  45. 2026-07-13 06:10 UTCEPSS rescore
  46. 2026-07-12 05:44 UTCEPSS rescore
  47. 2026-07-12 05:44 UTCEPSS rescore
  48. 2026-07-11 13:11 UTCOSV refresh
  49. 2026-07-11 08:25 UTCEPSS rescore
  50. 2026-07-11 08:25 UTCEPSS rescore
  51. 2026-07-09 19:07 UTCEPSS rescore
  52. 2026-07-08 15:12 UTCEPSS rescore
  53. 2026-07-07 13:43 UTCEPSS rescore
  54. 2026-07-06 16:25 UTCEPSS rescore
  55. 2026-07-06 02:21 UTCEPSS rescore
  56. 2026-07-06 02:21 UTCEPSS rescore
  57. 2026-07-05 02:28 UTCEPSS rescore
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  59. 2026-07-04 06:29 UTCEPSS rescore
  60. 2026-07-04 06:29 UTCEPSS rescore
  61. 2026-07-02 16:57 UTCEPSS rescore
  62. 2026-07-01 15:03 UTCEPSS rescore
  63. 2026-06-30 23:20 UTCEPSS rescore
  64. 2026-06-30 23:20 UTCEPSS rescore
  65. 2026-06-29 14:04 UTCEPSS rescore
  66. 2026-06-28 14:05 UTCEPSS rescore
  67. 2026-06-28 04:54 UTCEPSS rescore
  68. 2026-06-28 04:54 UTCEPSS rescore
  69. 2026-06-27 03:06 UTCEPSS rescore
  70. 2026-06-27 03:06 UTCEPSS rescore
  71. 2026-06-25 13:48 UTCEPSS rescore
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  73. 2026-06-24 14:03 UTCEPSS rescore
  74. 2026-06-24 14:03 UTCEPSS rescore
  75. 2026-06-23 21:31 UTCEPSS rescore

Frequently asked(5)

What is CVE-2020-8166?
CVE-2020-8166 is a medium vulnerability published on July 2, 2020. A CSRF forgery vulnerability exists in rails < 5.2.5, rails < 6.0.4 that makes it possible for an attacker to, given a global CSRF token such as the one present in the authenticity_token meta tag, forge a per-form CSRF token.
When was CVE-2020-8166 disclosed?
CVE-2020-8166 was first published in the National Vulnerability Database on July 2, 2020, with the most recent update on April 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-8166 actively exploited?
CVE-2020-8166 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2% probability of exploitation in the next 30 days, which ranks it in the top 24.2% of all scored CVEs.
What is the CVSS score of CVE-2020-8166?
CVE-2020-8166 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2020-8166?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-8166, 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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