CVE-2026-33195 — activestorage
Fix: rails/rails@4933c1eCVE-2026-33195 is a Path Traversal vulnerability in activestorage. A fix is available for activestorage — see the affected versions and patch details below.
Rails Active Storage has possible Path Traversal in DiskService
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33195.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
Real-World Exposure
activestorage💎activestorage💎activestorageReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, Active Storage's DiskService#path_for does not validate that the resolved filesystem path remains within the storage root directory. If a blob key containing path traversal sequences (e.g. ../) is used, it could allow reading, writing, or deleting arbitrary files on the server. Blob keys are expected to be trusted strings, but some applications could be passing user input as keys and would be affected. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | activestorage | ≥ 8.1.0.beta1&&< 8.1.2.1 | 8.1.2.1bundle update activestorage --conservative |
| 💎RubyGems | activestorage | ≥ 8.0.0.beta1&&< 8.0.4.1 | 8.0.4.1bundle update activestorage --conservative |
| 💎RubyGems | activestorage | all versions | 7.2.3.1bundle update activestorage --conservative |
Affected Products
railsrubyonrailsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for activestorage, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update activestorage to 8.1.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33195 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Red Hat Satellite: The Active Storage engine is explicitly commented out and disabled at runtime across all Satellite/Foreman builds. No Satellite plugin or component re-enables Active Storage. Hence, Red Hat Satellite is not affected.
To mitigate this issue, ensure that blob keys used by Active Storage are not derived from untrusted user input. Applications should validate and sanitize any user-provided data before it is used in blob keys to prevent path traversal sequences.Source: Red Hat security advisory for CVE-2026-33195 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-33195 in your dependencies?
Find it across RubyGems, including transitive dependencies.