Threat Intelligence / CVE / CVE-2026-17545

CVE-2026-17545 — PHP

CVSS v4.0 6.9 (Medium, derived from score) · Priority 3.5/10 · Published 2026-09-25

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. 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 — 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

Full detection coverage & IOCs for threats exploiting CVE-2026-17545 are available via the Threadlinqs MCP server (Purple tier). View plans →

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