CVE-2026-66066: Action Pack is a framework for handling and responding to web requests

Q: How do I fix CVE-2026-66066?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Q: Is CVE-2026-66066 being exploited?

CVE-2026-66066 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-66066 affect?

CVE-2026-66066 affects affected software. Severity is critical (CVSS 9.5). 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

Q: How urgent is CVE-2026-66066?

Priority 71/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

This week

CRITICAL 9.5REMOTE

CVE-2026-66066 is a critical-severity flaw (CVSS 9.5) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 arbitrar

Why this priority

Critical severity
EPSS top 2%: very likely to be exploited
Public exploit reference
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.5 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	26.5% (top 2%)
CISA exploited list	No
Weakness	CWE-1188
Published	2026-07-30
Last modified	2026-09-10

Publisher (CNA): GitHub, Inc.

Last updated 2026-09-10 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-07-30 19:18 UTCPublished CVE record published
2026-09-10 20:36 UTCUpdated Record last modified

Exact fixes by distribution

RubyGems · activestorage · FIXED · 7.2.3.2 · vulnerable: < 7.2.3.2 · source

bundle update activestorage bundle list | grep activestorage

Fedora ELN · rust-snpguest · FIXED · 0.11.0-1.eln159 · FEDORA-2026-baa01ba6c8 · source

sudo dnf upgrade --advisory=FEDORA-2026-baa01ba6c8

Fedora 46 · rust-sev · FIXED · 8.0.0-1.fc46 · FEDORA-2026-df06b5fb0c · source

sudo dnf upgrade --advisory=FEDORA-2026-df06b5fb0c

Debian 12 · rails · FIXED · 2:6.1.7.10+dfsg-1~deb12u3

sudo apt update && sudo apt install --only-upgrade rails dpkg --compare-versions "$(dpkg-query -W -f='${Version}' rails)" ge "2:6.1.7.10+dfsg-1~deb12u3" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · rails · FIXED · 2:7.2.2.2+dfsg-2~deb13u2

sudo apt update && sudo apt install --only-upgrade rails dpkg --compare-versions "$(dpkg-query -W -f='${Version}' rails)" ge "2:7.2.2.2+dfsg-2~deb13u2" && echo PATCHED || echo STILL-VULNERABLE

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: rails/rails-forensics-CVE-2026-66066 (30 stars)
GitHub PoC: Zer0SumGam3/CVE-2026-66066-POC (23 stars)
GitHub PoC: 0xsha/KindaRails2Shell (4 stars)
Write-up: ethiack.com/info-hub/research/kindarails2shell-rails-rce-cve-2026-66066
Write-up: thehackernews.com/2026/07/critical-rails-flaw-could-let.html
Metasploit: Ruby on Rails Active Storage Vips Arbitrary File Read and Remote Code Execution

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-66066?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-66066 being exploited?

CVE-2026-66066 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-66066 affect?

CVE-2026-66066 affects affected software. Severity is critical (CVSS 9.5). 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

How urgent is CVE-2026-66066?

Priority 71/100. Critical severity; EPSS top 2%: very likely to be exploited; Public exploit reference; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action

References

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