Authenticated code execution via incomplete Twig blocklist
Published Mar 4, 2026 · Updated Mar 4, 2026
Code injection in Craft CMS 4 and 5 allows remote authenticated users to execute arbitrary code through crafted Twig templates. The Twig non-Closure arrow-function handler accepts callback names that the incomplete PHP-function blocklist fails to reject, so template map operations can invoke dangerous functions. Exploitation requires allowAdminChanges in production, a compromised administrator account, or access to the System Messages utility; consequences include code execution, file reads, SSRF, and template injection.
Summary
What happened
Code injection in Craft CMS 4 and 5 allows remote authenticated users to execute arbitrary code through crafted Twig templates. The Twig non-Closure arrow-function handler accepts callback names that the incomplete PHP-function blocklist fails to reject, so template map operations can invoke dangerous functions. Exploitation requires allowAdminChanges in production, a compromised administrator account, or access to the System Messages utility; consequences include code execution, file reads, SSRF, and template injection.
The record
- CVE
- CVE-2026-28783
- Published
- Mar 4, 2026
- Updated
- Mar 4, 2026
- Vendor
- Pixel & Tonic
- Product
- Craft CMS
- Classifications
- CWE-184, CWE-94, CWE-1336, T1059
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 4, 2026CVE publishedPublication date reported by the CVE source.
- Mar 4, 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=>= 4.0.0-RC1, <= 4.17.0-beta.1
- Affected versionversion=>= 5.0.0-RC1, <= 5.9.0-beta.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
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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