Windows filesystem and stream API vulnerability in PHP by The PHP Group
CVE-2026-17545

6.9MEDIUM

Key Information:

Vendor

PHP Group

Status
PHP
Vendor
CVE Published:
25 September 2026

What is CVE-2026-17545?

On Windows systems, PHP's filesystem and stream APIs fail to appropriately reject reserved device names such as CON, PRN, AUX, NUL, and others when they appear in file paths. This oversight allows attackers to craft malicious filenames that, when processed, can lead to the opening of a device instead of a standard file. Consequently, this could cause applications to hang or block, as well as potentially exhaust worker processes due to improper handling of device inputs.

Affected Version(s)

PHP 8.2.* < 8.2.34

PHP 8.3.* < 8.3.35

PHP 8.4.* < 8.4.26

References

https://github.com/php/php-src/security/advisories/GHSA-9...
vendor-advisory

CVSS V4

Score:
6.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
Physical
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

@Crispr (GitHub)
@OSTIF-Derek
Shivam Mathur
Jakub Zelenka
.