Bug 2544529 (CVE-2026-103261)

Summary: CVE-2026-103261 tornado: tornado: Denial of Service (DoS) via unbounded query string parsing
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: akhatavk, anpicker, aos-team-art-private, asdas, bbrownin, bparees, dpaolell, dschmidt, ebourniv, eglynn, hasun, ikhan, jdelft, jfula, jjoyce, jlanda, jowilson, jpretori, jschluet, jupierce, jwong, kaycoth, kshier, lgarciaa, lhh, mbiarnes, mburns, mgarciac, nyancey, omaciel, ometelka, ppalepu, ppostler, prdhamdh, ptisnovs, rbobbitt, rhel-process-autobot, rjohnson, sbunciak, sghai, sidsharm, simaishi, stcannon, suppawar, syedriko, ttakamiy, vlaad, watson-tool-maintainers, xdharmai, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Tornado. When processing incoming HTTP requests, Tornado fails to restrict the number of parameters parsed from the URL query string. A remote, unauthenticated attacker could exploit this flaw by sending requests with an excessive number of query parameters, leading to high CPU consumption that stalls the application's event loop. This results in a Denial of Service (DoS), significantly degrading response times for all clients sharing the same server process.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2558171, 2558179, 2558181    
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Description OSIDB Bzimport 2026-10-01 10:56:12 UTC 
Tornado before 6.5.9 fails to limit the number of query string fields in HTTPServerRequest.__init__, allowing remote attackers to cause event-loop stalling by sending requests with thousands of query parameters. Attackers can send unauthenticated GET requests with unbounded query-string field counts to degrade response times for all clients sharing the same IOLoop.