CVE-2026-17545 — PHP on Windows: Reserved Device Names Are Not Rejected Before File/Stream I/O which can cause DoS
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…
Published: 2026-09-25 · CVSS: 6.9 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7