Authenticated RCE via permissive Twig sandbox allowlist
Published Aug 27, 2026 · Updated Aug 28, 2026
Protection mechanism failure in Craft CMS 4 before 4.18.3 and 5 before 5.10.7 allows remote authenticated users to execute server code. The Twig sandbox allowlist permits dangerous Yii framework functionality, so attacker-controlled template expressions escape intended restrictions. A valid low-privilege account and network access to a vulnerable Twig-processing path are required; successful exploitation compromises the application server.
Summary
What happened
Protection mechanism failure in Craft CMS 4 before 4.18.3 and 5 before 5.10.7 allows remote authenticated users to execute server code. The Twig sandbox allowlist permits dangerous Yii framework functionality, so attacker-controlled template expressions escape intended restrictions. A valid low-privilege account and network access to a vulnerable Twig-processing path are required; successful exploitation compromises the application server.
The record
- CVE
- CVE-2026-79988
- Published
- Aug 27, 2026
- Updated
- Aug 28, 2026
- Vendor
- Pixel & Tonic
- Product
- Craft CMS
- Classifications
- CWE-693, T1059
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 27, 2026CVE publishedPublication date reported by the CVE source.
- Aug 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=4.0.0-RC1 <4.18.3
- Affected versionversion=5.0.0-RC1 <5.10.7
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
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo