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High · 7.5 Scanner template CVE-2026-5032 EUVD-2026-18136

W3 Total Cache <= 2.9.3 - Unauthenticated Security Token Exposure via User-Agent Header

Published Apr 2, 2026 · Updated Apr 8, 2026 · Assigned by Wordfence

Description

The W3 Total Cache plugin for WordPress is vulnerable to information exposure in all versions up to, and including, 2.9.3. This is due to the plugin bypassing its entire output buffering and processing pipeline when the request's User-Agent header contains "W3 Total Cache", which causes raw mfunc/mclude dynamic fragment HTML comments — including the W3TC_DYNAMIC_SECURITY security token — to be rendered in the page source. This makes it possible for unauthenticated attackers to discover the value of the W3TC_DYNAMIC_SECURITY constant by sending a crafted User-Agent header to any page that contains developer-placed dynamic fragment tags, granted the site has the fragment caching feature enabled. With the leaked W3TC_DYNAMIC_SECURITY token, an attacker can craft valid mfunc tags to execute arbitrary PHP code on the server, achieving remote code execution.

Affected products

VendorProductAffectedFixed
boldgrid W3 Total Cache ≤ 2.9.3 —

Automated scanner template

A ready-made Nuclei template detects this vulnerability automatically. Vulnerabilities with public scanner templates are typically probed across the internet soon after the template appears — exposed systems should be patched first.

Source: projectdiscovery/nuclei-templates (MIT) — updated daily. Only links are listed.

References