Bug 2541645 (CVE-2026-17545)

Summary: CVE-2026-17545 php: PHP: Denial of Service via reserved device names on Windows
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in PHP. When running on Windows environments, PHP's filesystem and stream handlers fail to reject reserved system device names in file paths. An attacker who can control file or stream paths can supply these reserved names to open system devices instead of standard files. This can cause application worker processes to block or hang indefinitely, resulting in a Denial of Service (DoS) through resource exhaustion.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-09-25 20:57:36 UTC
On Windows, PHP's filesystem and stream APIs do not reject reserved device names such as CON, PRN, AUX, NUL, COM1 to COM9, LPT1 to LPT9, CONIN$ and CONOUT$ when they appear as a component of a path. An attacker-controlled filename therefore reaches CreateFileW() and opens a device instead of the regular file the application expected, which can block or hang the request and exhaust worker processes.