Rails Active Storage has a possible DoS vulnerability when in proxy mode via Range requestsGHSA-r46p-8f7g-vvvg
Fix: rails/rails@2cd933cGHSA-r46p-8f7g-vvvg is a CWE-789 vulnerability in activestorage. A fix is available for activestorage — see the affected versions and patch details below.
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.
- 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 GHSA-r46p-8f7g-vvvg.
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
Impact
When serving files through Active Storage's Blobs::ProxyController, the controller loads the entire requested byte range into memory before sending it. A request with a large or unbounded Range header (e.g. bytes=0-) could cause the server to allocate memory proportional to the file size, possibly resulting in a DoS vulnerability through memory exhaustion.
Releases
The fixed releases are available at the normal locations.
Credit
This issue was responsibly reported by Hackerone user pirikara
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 GHSA-r46p-8f7g-vvvg is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
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.
This vulnerability is rated a Moderate by Red Hat. Successful exploitation of this vulnerability depends on specific application deployment conditions and configurations within Active Storage, including the use of proxy delivery mode and the presence of sufficiently large files accessible to the attacker.…
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-r46p-8f7g-vvvg (CC BY 4.0)
Frequently Asked Questions
Is GHSA-r46p-8f7g-vvvg in your dependencies?
Find it across RubyGems, including transitive dependencies.