Authenticated service interrupt via regex_replace backtracking
Published Aug 19, 2026 · Updated Aug 19, 2026
Regular expression denial of service in Grav before 2.0.4 allows remote authenticated users to interrupt service via Twig page content. The Twig sandbox allowlists regex_replace in system/config/security.yaml, and GravExtension::regexReplace() passes an editor-controlled pattern directly to preg_replace(), allowing catastrophic backtracking to pin PHP worker CPU. Exposure requires security.twig_content.process_enabled to be enabled and page-edit access; affected requests can stall a worker or, on small PHP-FPM pools, make the site unresponsive for visitors.
Summary
What happened
Regular expression denial of service in Grav before 2.0.4 allows remote authenticated users to interrupt service via Twig page content. The Twig sandbox allowlists regex_replace in system/config/security.yaml, and GravExtension::regexReplace() passes an editor-controlled pattern directly to preg_replace(), allowing catastrophic backtracking to pin PHP worker CPU. Exposure requires security.twig_content.process_enabled to be enabled and page-edit access; affected requests can stall a worker or, on small PHP-FPM pools, make the site unresponsive for visitors.
The record
- CVE
- CVE-2026-62672
- Published
- Aug 19, 2026
- Updated
- Aug 19, 2026
- Vendor
- Grav
- Product
- Grav
- Classifications
- CWE-1333, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 19, 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=< 2.0.4
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
- GitHub advisory PoC for regex_replace ReDoSproof of concept · demonstrated
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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