# CVE-2026-57311 — JCD Windu CMS

> As of 2026-07-20, CVE-2026-57311 is a Medium-severity (band derived from the CVSS v4.0 score, not stated by the CNA) vulnerability in JCD Windu CMS, CVSS v4.0 5.3, EPSS 0.3% (29.7th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-57311, most recently “CVE-2026-57309: Unauthenticated Blind SQL Injection in Windu CMS 4.1 (with CVE-2026-57310 Weak Password Hashing and CVE-2026-57311 Unrestricted File Upload)”.

**Last updated:** 2026-07-20

## What is CVE-2026-57311?

Windu CMS does not validate types of uploaded files. An authenticated attacker can upload arbitrary files, including PHP. This can lead to Remote Code Execution. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 4.1 but may also affect other versions.

The record classifies CVE-2026-57311 under weakness class [CWE-434](https://cwe.mitre.org/data/definitions/434.html). 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 55 days ago.

## Severity and exploitation probability

- **CVSS v4.0 base score:** 5.3 — Medium (derived from score) (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:L`)
- **EPSS (FIRST):** 0.3% probability of exploitation in the next 30 days, higher than 29.7% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-07-20

## Is CVE-2026-57311 being exploited?

No public exploitation evidence for CVE-2026-57311 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-07-20. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.

## Affected products and versions

- **JCD**: Windu CMS

## How to fix CVE-2026-57311

No vendor patch reference has been recorded for CVE-2026-57311 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-2026-57311

1 tracked threat in the Threadlinqs corpus references CVE-2026-57311, either in the campaign’s CVE list or as an indicator on the campaign record.

- [CVE-2026-57309: Unauthenticated Blind SQL Injection in Windu CMS 4.1 (with CVE-2026-57310 Weak Password Hashing and CVE-2026-57311 Unrestricted File Upload)](https://intel.threadlinqs.com/threat/TL-2026-1568) — HIGH · 2026-07-20

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-07-22. This product uses the NVD API but is not endorsed or certified by the NVD.

**Third-party advisory**

- [cert.pl — third party advisory](https://cert.pl/posts/2026/07/CVE-2026-57309)

**Issue tracking and product pages**

- [windu.org — product](https://windu.org/)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-57311
Full detection coverage and IOCs for threats exploiting CVE-2026-57311 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp