Bug 2451983 (CVE-2026-33658)

Summary: CVE-2026-33658 rails: activestorage: Active Storage: Denial of Service via HTTP Range header processing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: anthomas, ehelms, ggainey, juwatts, mhulan, nmoumoul, osousa, pcreech, rchan, smallamp, tmalecek
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Active Storage, a component of Rails applications that handles file attachments. A remote attacker could exploit this vulnerability by sending a specially crafted HTTP request with an excessive number of small byte ranges in the HTTP Range header. This action causes the Active Storage proxy controller to consume a disproportionate amount of CPU resources, leading to a Denial of Service (DoS) condition. This could make the affected Rails application unresponsive or unavailable to legitimate users.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2452166, 2452165    
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Description OSIDB Bzimport 2026-03-26 22:02:03 UTC
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 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. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.