# CVE-2026-17545 — PHP

> As of 2026-09-25, CVE-2026-17545 is a Medium-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in PHP, CVSS v4.0 6.9. Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-17545, most recently “Multiple PHP Vulnerabilities Enable Denial of Service, TLS Verification Bypass, and Credential Leakage (CVE-2026-91765, CVE-2026-91768, CVE-2026-6103 and 8 Others) — GovCERT.HK A26-09-40”.

**Last updated:** 2026-09-25

## What is 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.

The record classifies CVE-2026-17545 under weakness class [CWE-67](https://cwe.mitre.org/data/definitions/67.html). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 1 day ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 6.9 — Medium (derived from score) (`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`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-25

## Is CVE-2026-17545 being exploited?

No public exploitation evidence for CVE-2026-17545 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-09-25. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

## Affected products and versions

- **PHP Group**: PHP

## How to fix CVE-2026-17545

No vendor patch reference has been recorded for CVE-2026-17545 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-17545

1 tracked threat in the Threadlinqs corpus references CVE-2026-17545, either in the campaign’s CVE list or as an indicator on the campaign record.

- [Multiple PHP Vulnerabilities Enable Denial of Service, TLS Verification Bypass, and Credential Leakage (CVE-2026-91765, CVE-2026-91768, CVE-2026-6103 and 8 Others) — GovCERT.HK A26-09-40](https://intel.threadlinqs.com/threat/TL-2026-2658) — MEDIUM · 2026-09-25

## Sources

Enriched from CVE.org, NVD. Last verified by Threadlinqs on 2026-09-26. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/php/php-src/security/advisories/GHSA-9f67-6fw4-hpfp)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-17545
Full detection coverage and IOCs for threats exploiting CVE-2026-17545 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp