Rails Active Storage has a possible DoS vulnerability in proxy mode via multi-range requestsGHSA-p9fm-f462-ggrg
MEDIUMGHSA-p9fm-f462-ggrg is a medium-severity (CVSS 6.5) CWE-770 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’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-p9fm-f462-ggrg.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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
Active Storage's proxy controller does not limit the number of byte ranges in an HTTP Range header. A request with thousands of small ranges causes disproportionate CPU usage compared to a normal request for the same file, possibly resulting in a DoS vulnerability.
Releases
The fixed releases are available at the normal locations.
Credit
This issue was responsibly reported by Hackerone researcher thwin_htet.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | activestorage | ≥ 8.1.0&&< 8.1.2.1 | 8.1.2.1bundle update activestorage --conservative |
| 💎RubyGems | activestorage | ≥ 8.0.0&&< 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-p9fm-f462-ggrg 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.
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-p9fm-f462-ggrg (CC BY 4.0)
Frequently Asked Questions
Is GHSA-p9fm-f462-ggrg in your dependencies?
Find it across RubyGems, including transitive dependencies.