# CVE-2026-6433 — Custom css-js-php

> As of 2026-05-11, CVE-2026-6433 is a HIGH-severity vulnerability in Custom css-js-php, CVSS v3.1 7.3, EPSS 0.7% (50.6th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-6433, most recently “WP-SHELLSTORM: Exposed Chinese-Speaking Threat Actor Server Reveals Mass WordPress/Joomla Webshell Brokerage Targeting 1.4M Domains via CVE-2026-48907 (Joomla JCE) and CVE-2021-29441 (Nacos)”.

**Last updated:** 2026-05-11

## What is CVE-2026-6433?

The Custom css-js-php WordPress plugin through 2.0.7 does not properly sanitize user input before using it in a SQL query, and the result is passed to eval(), allowing unauthenticated users to execute arbitrary PHP code on the server.

Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 147 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.3 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`)
- **EPSS (FIRST):** 0.7% probability of exploitation in the next 30 days, higher than 50.6% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 8.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-05-11

## Is CVE-2026-6433 being exploited?

Weaponised exploit code for CVE-2026-6433 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (`http/cves/2026/CVE-2026-6433.yaml`).

- [murrez/CVE-2026-6433](https://github.com/murrez/CVE-2026-6433) (github)
- [trickest/cve](https://github.com/trickest/cve/blob/main/2026/CVE-2026-6433.md) (trickest)

## Affected products and versions

- **(vendor unspecified)**: Custom css-js-php

## How to fix CVE-2026-6433

No vendor patch reference has been recorded for CVE-2026-6433 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-2026-6433

1 tracked threat in the Threadlinqs corpus references CVE-2026-6433, either in the campaign’s CVE list or as an indicator on the campaign record.

- [WP-SHELLSTORM: Exposed Chinese-Speaking Threat Actor Server Reveals Mass WordPress/Joomla Webshell Brokerage Targeting 1.4M Domains via CVE-2026-48907 (Joomla JCE) and CVE-2021-29441 (Nacos)](https://intel.threadlinqs.com/threat/TL-2026-1180) — HIGH · 2026-07-10

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories, ProjectDiscovery Nuclei. Last verified by Threadlinqs on 2026-07-10. This product uses the NVD API but is not endorsed or certified by the NVD.

**Exploit and proof of concept**

- [wpscan.com — exploit](https://wpscan.com/vulnerability/a0b1c059-e156-4402-ac8d-67f8ad7386cc/)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-6433
Full detection coverage and IOCs for threats exploiting CVE-2026-6433 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp