CVE-2026-66066

CRITICALPre-NVD 9.59.5—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 27.9%, top 2% 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, secondary
Weaponized
9.5EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • Public exploit code is available (Metasploit, ssvc poc, epss top5pct, public exploit)
CISA-KEV: Not listedEPSS PROB: 28%CVSS: 9.5Exploit: Metasploit · ssvc poc · epss top5pct · public exploitExposed: 0

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

Action Pack is a framework for handling and responding to web requests. In versions prior to 7.2.3.2, 8.0.5.1 and 8.1.3.1, Active Storage does not disable libvips operations marked unsafe for untrusted content, allowing a crafted upload to invoke such an operation. Consuming applications are affected when configured to use libvips and accept image uploads from untrusted users. An unauthenticated attacker may exploit this behavior to read arbitrary files accessible to the Rails process, including environment variables and application secrets. Exposure of credentials such as secret_key_base or external-service tokens may enable remote code execution or lateral movement. This issue has been fixed in versions 7.2.3.2, 8.0.5.1 and 8.1.3.1.

CVSS v3
9.5
EG Score
9.5(medium)
EG Risk
84(Attend)
EG Risk 84/100SSVC: Attend

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
Severity95% × 45%
Exploitation65% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
28%
EPSS %ILE
98%
KEV
Not listed

Published

July 30, 2026

Last Modified

September 10, 2026

Advisory Details (10)

Auto-updated Sep 14, 2026
⚠️ Active exploitation confirmed. Patch available. Sources: github_commit, github_release, github.
generic

oss-security - Rails CVE-2026-66066: Possible arbitrary file read and remote code execution in Active Storage variant processing

http://www.openwall.com/lists/oss-security/2026/07/29/9
generic🔴 Active Exploitation

Critical Rails Flaw Could Let Unauthenticated Attackers Read Server Files via Image Uploads

https://thehackernews.com/2026/07/critical-rails-flaw-could-let.html
generic

ruby-advisory-db/gems/activestorage/CVE-2026-66066.yml at master · rubysec/ruby-advisory-db · GitHub

https://github.com/rubysec/ruby-advisory-db/blob/master/gems/activestorage/CVE-2026-66066.yml
github Patch Available

Possible arbitrary file read and remote code execution in Active Storage variant processing · Advisory · rails/rails · GitHub

https://github.com/rails/rails/security/advisories/GHSA-xr9x-r78c-5hrm
github_release Patch Available

8.1.3.1

Patch available: rails/rails v8.1.3.1

https://github.com/rails/rails/releases/tag/v8.1.3.1
github_release Patch Available

8.0.5.1

Patch available: rails/rails v8.0.5.1

https://github.com/rails/rails/releases/tag/v8.0.5.1
github_release Patch Available

7.2.3.2

Patch available: rails/rails v7.2.3.2

https://github.com/rails/rails/releases/tag/v7.2.3.2
github_commit

commit d79b7f4aa17d (rails/rails)

Fix landed in rails/rails commit d79b7f4aa17d — awaiting tagged release

https://github.com/rails/rails/commit/d79b7f4aa17dec8ce4960fef05733c8c0c7ef49a
github_commit

commit 349e7a5d5b4b (rails/rails)

Fix landed in rails/rails commit 349e7a5d5b4b — awaiting tagged release

https://github.com/rails/rails/commit/349e7a5d5b4b715af1e416db824f3c078a7d59e5
github_commit

commit 1c01bb587206 (rails/rails)

Fix landed in rails/rails commit 1c01bb587206 — awaiting tagged release

https://github.com/rails/rails/commit/1c01bb587206ee6eb0e1179c2cef96a6a47acb1e

Vendor Advisories for CVE-2026-66066(1)

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

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
rails2:6.0.3.7+dfsg-2 ... 2:7.2.3.2+dfsg-2 (72 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
rails2:6.1.7.10+dfsg-1~deb12u1 ... 2:7.2.3.2+dfsg-2 (38 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
rails2:7.2.2.1+dfsg-7 ... 2:7.2.3.2+dfsg-2 (10 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
rails2:7.2.2.1+dfsg-7 ... 2:7.2.3.1+dfsg-1 (8 versions)2:7.2.3.2+dfsg-1—
RubyGems(1)
PackageVulnerable rangeFixed inDependents
activestorage8.1.0 ... 8.1.3 (7 versions)8.1.3.1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 46× 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. 2026-09-18 22:25 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 01:18 UTCEG score recompute
  4. 2026-09-17 01:28 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
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  8. 2026-09-15 03:14 UTCEG score recompute
  9. 2026-09-12 16:36 UTCEG score recompute
  10. 2026-09-11 14:59 UTCEG score recompute
  11. 2026-09-11 14:53 UTCEPSS rescore
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  13. 2026-09-10 12:58 UTCEG score recompute
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  24. 2026-09-01 22:36 UTCEG score recompute
  25. 2026-09-01 13:54 UTCEPSS rescore
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  1. 2026-09-01 07:29 UTCEG score recompute
  2. 2026-09-01 04:40 UTCEPSS rescore
  3. 2026-08-30 22:21 UTCEG score recompute
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  9. 2026-08-27 20:48 UTCEG score recompute
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  14. 2026-08-24 15:46 UTCEG score recompute
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  17. 2026-08-23 00:19 UTCEPSS rescore
  18. 2026-08-21 23:55 UTCEG score recompute
  19. 2026-08-21 23:49 UTCEPSS rescore
  20. 2026-08-21 00:04 UTCEG score recompute
  21. 2026-08-20 22:56 UTCEPSS rescore
  22. 2026-08-19 19:59 UTCEG score recompute
  23. 2026-08-19 17:04 UTCEPSS rescore
  24. 2026-08-18 15:53 UTCEG score recompute
  25. 2026-08-18 13:48 UTCEPSS rescore
  26. 2026-08-17 19:43 UTCEG score recompute
  27. 2026-08-17 13:47 UTCEPSS rescore
  28. 2026-08-16 17:22 UTCEG score recompute
  29. 2026-08-16 14:56 UTCEPSS rescore
  30. 2026-08-16 05:27 UTCEG score recompute
  31. 2026-08-15 01:41 UTCEG score recompute
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  34. 2026-08-13 22:00 UTCEPSS rescore
  35. 2026-08-12 14:09 UTCEG score recompute
  36. 2026-08-12 13:51 UTCEPSS rescore
  37. 2026-08-11 14:20 UTCEG score recompute
  38. 2026-08-11 02:26 UTCEG score recompute
  39. 2026-08-11 00:00 UTCEPSS rescore
  40. 2026-08-08 18:52 UTCEG score recompute
  41. 2026-08-08 16:37 UTCEPSS rescore
  42. 2026-08-07 19:04 UTCEG score recompute
  43. 2026-08-06 15:18 UTCEG score recompute
  44. 2026-08-06 13:47 UTCEPSS rescore
  45. 2026-08-05 19:28 UTCEG score recompute
  46. 2026-08-05 19:17 UTCEPSS rescore
  47. 2026-08-05 19:17 UTCEPSS rescore
  48. 2026-08-04 18:02 UTCEG score recompute
  49. 2026-08-04 15:10 UTCEPSS rescore
  50. 2026-08-04 13:58 UTCEG score recompute
  51. 2026-08-04 10:39 UTCEPSS rescore
  52. 2026-08-04 05:28 UTCEG score recompute
  53. 2026-08-03 12:08 UTCEG score recompute
  54. 2026-08-03 10:36 UTCEPSS rescore
  55. 2026-08-02 04:17 UTCEG score recompute
  56. 2026-08-02 02:27 UTCEPSS rescore
  57. 2026-08-01 08:25 UTCEG score recompute
  58. 2026-08-01 07:33 UTCEG score recompute
  59. 2026-08-01 04:23 UTCEG score recompute
  60. 2026-08-01 04:16 UTCEPSS rescore
  61. 2026-07-31 20:24 UTCEG score recompute
  62. 2026-07-31 16:25 UTCEG score recompute
  63. 2026-07-30 19:30 UTCEG score recompute
  64. 2026-07-30 18:56 UTCEG score recompute
  65. 2026-07-30 18:55 UTCMITRE cvelistV5first tracked

Publicly available exploits

(6 references)

Working exploit code is in the public domain (1 Metasploit module) (5 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCHackSpeak/kindarails2shell-poc
    First seen Aug 3, 2026

    CVE-2026-66066 (KindaRails2Shell) PoC - Rails Active Storage/libvips arbitrary file read to RCE; for authorized security testing

    Open source ↗
  • GitHub PoCHackSpeak/CVE-2026-66066
    First seen Aug 3, 2026

    CVE-2026-66066 (KindaRails2Shell) PoC - Rails Active Storage/libvips arbitrary file read to RCE; for authorized security testing

    Open source ↗
  • GitHub PoC0xsha/KindaRails2Shell
    First seen Jul 31, 2026

    CVE-2026-66066 + File Read, RCE, Scanner, Lab

    Open source ↗
  • GitHub PoCrails/rails-forensics-CVE-2026-66066
    First seen Jul 30, 2026
    Open source ↗
  • GitHub PoCZer0SumGam3/CVE-2026-66066-POC
    First seen Jul 29, 2026

    PoC for CVE-2026-66066 in Ruby on Rails

    Open source ↗
  • Metasploitexploit/multi/http/rails_activestorage_vips_rce✓ verified
    First seen Jul 29, 2026

    Ruby on Rails Active Storage Vips Arbitrary File Read and Remote Code Execution

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-66066?
CVE-2026-66066 is a critical vulnerability published on July 30, 2026. Action Pack is a framework for handling and responding to web requests. In versions prior to 7.2.3.2, 8.0.5.1 and 8.1.3.1, Active Storage does not disable libvips operations marked unsafe for untrusted content, allowing a crafted upload to invoke such an operation. Consuming applications are…
When was CVE-2026-66066 disclosed?
CVE-2026-66066 was first published in the National Vulnerability Database on July 30, 2026, with the most recent update on September 10, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66066 actively exploited?
CVE-2026-66066 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 28% probability of exploitation in the next 30 days, which ranks it in the top 2.0% of all scored CVEs.
What is the CVSS score of CVE-2026-66066?
CVE-2026-66066 has a CVSS v3 base score of 9.5 (NVD).
How do I remediate CVE-2026-66066?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66066, 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-2026-66066

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