Bug 2556124

Summary: CVE-2026-76151 qt6-qtbase: QtNetwork: Denial of Service via excessively large HTTP Cache-Control header [fedora-43]
Product: [Fedora] Fedora Reporter: Vladimir Vasilev <vvasilev>
Component: qt6-qtbaseAssignee: Jan Grulich <jgrulich>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: 43CC: jgrulich, kde-sig
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["7628bd79-fdff-4c23-a22b-d547a232bab7"]}
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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:    
Bug Blocks: 2535100    

Description Vladimir Vasilev 2026-10-20 10:56:13 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Out-of-bounds read (buffer over-read) in the HTTP Cache-Control response header parsing in the QtNetwork module in Qt Group Qt 6.0.0 through 6.8.8, and 6.9.0 through 6.11.1, allows remote attackers to cause a denial of service (application crash) via an excessively large Cache-Control header value returned by an untrusted or compromised HTTP server to an application using QNetworkAccessManager. Only the client side of the connection is affected and 32-bit builds are not affected; the out-of-bounds access is read-only, with no information disclosure and no code execution.