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.

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Fixes

Solution

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Workaround

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History

Sat, 26 Sep 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-66
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Fri, 25 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 25 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Description 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.
Title PHP on Windows: Reserved Device Names Are Not Rejected Before File/Stream I/O which can cause DoS
Weaknesses CWE-67
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: php

Published:

Updated: 2026-09-25T20:43:34.157Z

Reserved: 2026-07-27T10:15:15.310Z

Link: CVE-2026-17545

cve-icon Vulnrichment

Updated: 2026-09-25T20:43:29.843Z

cve-icon NVD

Status : Received

Published: 2026-09-25T21:17:23.253

Modified: 2026-09-25T21:17:23.253

Link: CVE-2026-17545

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-25T20:18:11Z

Links: CVE-2026-17545 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-25T22:15:08Z

Weaknesses