Bug 2500583 (CVE-2026-47736)

Summary: CVE-2026-47736 puma: Puma: Denial of Service due to unbounded memory growth in PROXY protocol v1
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: akostadi, amasferr, anthomas, dmayorov, ehelms, eshamard, ggainey, jlledo, jpasqual, juwatts, jvasik, kaycoth, mhulan, nmoumoul, osousa, pantinor, pcreech, rblanco, rchan, rhel-process-autobot, smallamp, tmalecek, tsedmik, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Puma, a Ruby/Rack web server. When PROXY protocol v1 support is enabled, a remote attacker can continuously send data without proper termination. This causes the server to consume an increasing amount of memory and CPU resources, leading to a Denial of Service (DoS) where the server becomes unresponsive or crashes.
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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: 2500848    
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Description OSIDB Bzimport 2026-07-14 20:04:41 UTC
Puma is a Ruby/Rack web server built for parallelism. From 5.5.0 until 7.2.1 and 8.0.2, when PROXY protocol v1 support is enabled, Puma reads incoming bytes into an internal buffer while waiting for CRLF to determine whether a PROXY v1 line is present, allowing an attacker that continuously sends bytes without CRLF to cause unbounded in-process memory growth and additional CPU cost from repeatedly scanning the growing buffer. This issue is fixed in versions 7.2.1 and 8.0.2.