The activestorage gem before 8.1.4.1 for Ruby on Rails, when ImageMagick attachment processing occurs, can allow server read and write…
Affects the activestorage gem in Ruby on Rails before 8.0.5.2 and 8.1 before 8.1.4.1 when ImageMagick processes attachments under a policy that does not deny the involved coders. Fixed in 8.0.5.2 and 8.1.4.1.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 8.0.5.2, 8.1.4.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 8.0.5.2, 8.1.4.1.
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Data gap: Advisories don't say whether default setups are affected
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity9.8/10CVSS 9.8
- No patch0/5No signal
What would change the score
- Would score about 72 if added to CISA KEV
- Would score about 67 if CISA's SSVC rates exploitation active
- Would score about 32 if advisories confirm default setups are exposed
CVE-2026-122006 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.8 (critical) and affects Active Storage; fixed in 8.0.5.2 and 8.1.4.1.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 27/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Fix
- Fixed in 8.0.5.2, 8.1.4.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The activestorage gem for Ruby on Rails, before the fixed release, is affected when ImageMagick processes attached files. Remotely, without logging in, an attacker can read and write files on the server, such as the secret_key_base, because no ImageMagick security policy blocks the unintended functionality.
Read the original description
The activestorage gem before 8.1.4.1 for Ruby on Rails, when ImageMagick attachment processing occurs, can allow server read and write operations (e.g., reading secret_key_base) because the ImageMagick analyzer runs when a file is attached, and there is not an ImageMagick security policy to block unintended functionality.
What to do
Upgrade to a fixed version: 8.0.5.2, 8.1.4.1.
Workaround: Copy the rules of the shipped ImageMagick policy.xml into the system policy, at minimum denying the MSL coder, the Ghostscript coders, and the gs delegate
Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
- Record last updated
Affected versions
- rubyonrails Active Storage
fixed in 8.0.5.2; From 8.1 · fixed in 8.1.4.1
Evidence 5
- Advisory
- Repository
- Repository
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-122006
Is CVE-2026-122006 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
When ImageMagick processes Active Storage attachments, an unauthenticated attacker may be able to write arbitrary files on the server. With the Disk service, they may also read files the application process can read, such as secret_key_base and credentials, which could lead to remote code execution or lateral movement.Source: github.com
Which versions are affected by CVE-2026-122006?
Active Storage: before 8.0.5.2; from 8.1 before 8.1.4.1.Source: cve.now feed data
Am I affected, and how do I check?
Affected are activestorage versions before 8.0.5.2 and the 8.1 line before 8.1.4.1. The setup also needs ImageMagick as the variant processor (mini_magick), an ImageMagick policy that does not already deny the MSL and Ghostscript coders, and file uploads from untrusted users. Check the activestorage version in the application's dependencies and the configured variant processor.Source: github.com
How do I fix CVE-2026-122006?
Upgrade activestorage to 8.0.5.2 or later on the 8.0 line, or to 8.1.4.1 or later on the 8.1 line.Source: github.com