CVE-2026-17545
Description
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.
Statement
This vulnerability is specific to PHP on Windows, where reserved device names in attacker-controlled paths can open devices and hang worker processes. Red Hat Enterprise Linux and other Red Hat products ship PHP for Linux only, so the vulnerable Windows path-handling code is not present. The Moderate rating reflects the upstream Windows denial-of-service impact; Red Hat product deployments are not affected.
Mitigation
No action is required for Red Hat Enterprise Linux or other Linux-based Red Hat products, which do not implement Windows reserved device-name handling. On Windows PHP deployments, upgrade to a fixed PHP release and reject user-controlled path components that resolve to reserved device names.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | 7.5 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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