Vulnerability in PHP
CVE-2026-17545
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (30.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000
Affected products
Weakness classification (CWE)
References
- github.com/php/php-src/security/advisories/GHSA-9f67-6fw4-hpfp (Exploit, vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-17545?
- CVE-2026-17545 is a high-severity vulnerability in PHP, classified under CWE-67. CVSS score: 7.5/10. Published 2026-09-25.
- How severe is CVE-2026-17545?
- High severity. CVSS v3 base score is 7.5 out of 10.