Unauthenticated PHP execution via unquoted mfunc token
Published Mar 5, 2026 · Updated Mar 5, 2026
Code injection in BoldGrid W3 Total Cache 2.9.1 and earlier allows remote attackers to execute arbitrary PHP through crafted comments. The dynamic-fragment parser interpolates W3TC_DYNAMIC_SECURITY into a regular expression without quoting it and passes matched mfunc content to eval(). Exploitation requires dynamic fragment caching, a regex-metacharacter security token, and a comment path that preserves the crafted tag; successful requests run code as the PHP worker.
Summary
What happened
Code injection in BoldGrid W3 Total Cache 2.9.1 and earlier allows remote attackers to execute arbitrary PHP through crafted comments. The dynamic-fragment parser interpolates W3TC_DYNAMIC_SECURITY into a regular expression without quoting it and passes matched mfunc content to eval(). Exploitation requires dynamic fragment caching, a regex-metacharacter security token, and a comment path that preserves the crafted tag; successful requests run code as the PHP worker.
The record
- CVE
- CVE-2026-27384
- Published
- Mar 5, 2026
- Updated
- Mar 5, 2026
- Vendor
- Web Ventures
- Product
- W3 Total Cache
- Classifications
- CWE-1284, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 5, 2026CVE publishedPublication date reported by the CVE source.
- Mar 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=n/a <=<= 2.9.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- xxconi CVE-2026-27384 mfunc exploitfunctional · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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