Skip to main content

Grav CMS EUVDEUVD-2026-45083

| CVE-2026-62237 MEDIUM
Inefficient Regular Expression Complexity (ReDoS) (CWE-1333)
2026-07-17 VulnCheck GHSA-6gqg-9qjp-56jm
6.0
CVSS 4.0 · Vendor: VulnCheck
Share

Severity by source

Vendor (VulnCheck) PRIMARY
6.0 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today AI
6.5 MEDIUM

Network vector with low-privilege authentication required; no confidentiality or integrity impact; high availability impact via CPU exhaustion of the web worker process.

3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
X

Lifecycle Timeline

2
Patch available
Jul 17, 2026 - 02:32 EUVD
Analysis Generated
Jul 17, 2026 - 01:01 vuln.today

DescriptionCVE.org

Grav before 2.0.4 contains a regular expression denial of service (ReDoS) vulnerability in the regex_replace filter and function, which are allowlisted in the Twig content sandbox. When Twig processing in page content is enabled (security.twig_content.process_enabled: true, disabled by default), an authenticated page editor can supply a catastrophically backtracking PCRE pattern that is passed directly to PHP's preg_replace(), causing unbounded CPU consumption and denial of service to the web server process.

AnalysisAI

ReDoS in Grav CMS's Twig sandbox allows an authenticated page editor to crash the web server process via a catastrophically backtracking PCRE pattern supplied to the regex_replace filter. Affected versions are all Grav releases prior to 2.0.4. Exploitation requires a non-default configuration (security.twig_content.process_enabled: true) and at least page-editor-level authentication, limiting blast radius to deployments that have deliberately unlocked Twig processing in page content. No public exploit code or CISA KEV listing has been identified at time of analysis.

Technical ContextAI

Grav (CPE: cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:*) is a PHP-based flat-file CMS that uses Twig as its templating engine. The vulnerability stems from CWE-1333 (Inefficient Regular Expression Complexity): the regex_replace Twig filter and function are allowlisted inside Grav's Twig content sandbox and pass user-controlled PCRE patterns directly to PHP's native preg_replace(). PHP's PCRE engine uses recursive backtracking that, when given a pattern with ambiguous quantifiers on overlapping character classes, can degrade to exponential time complexity - consuming all available CPU before returning a result. Because preg_replace() executes synchronously within the PHP web worker process, a single crafted request is sufficient to block that worker indefinitely, effectively removing it from the server pool.

RemediationAI

The primary fix is to upgrade Grav to version 2.0.4 or later, as confirmed by the vendor security advisory at https://github.com/getgrav/grav/security/advisories/GHSA-37f3-6p89-6qr9. If an immediate upgrade is not possible, the most effective compensating control is to ensure security.twig_content.process_enabled remains set to false (its default value) in the Grav configuration - this completely blocks the attack path by preventing user-supplied content from being processed as Twig templates. The trade-off is that any legitimate Twig templating in page content will cease to function. Additionally, administrators should audit whether any page-editor-role accounts belong to untrusted or external users, and if so, consider demoting them until the patch is applied. There is no known way to safely permit process_enabled: true without patching, since the underlying PCRE passthrough is the root cause.

More in Grav

View all
CVE-2025-66294 HIGH POC
8.8 Dec 01

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, a Server-Side Template Injection (SSTI) vulnerability exists

CVE-2025-66301 CRITICAL POC
9.6 Dec 01

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, due to improper authorization checks when modifying critical

CVE-2025-50286 HIGH POC
8.1 Aug 06

A Remote Code Execution (RCE) vulnerability in Grav CMS v1.7.48 allows an authenticated admin to upload a malicious plug

CVE-2024-34082 CRITICAL POC
9.9 May 15

Grav is a file-based Web platform. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low a

CVE-2021-47812 CRITICAL POC
9.8 Jan 16

GravCMS 1.10.7 allows unauthenticated remote attackers to write arbitrary YAML configuration files, leading to full serv

CVE-2025-66297 HIGH POC
8.8 Dec 01

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, a user with admin panel access and permissions to create or e

CVE-2025-66299 HIGH POC
8.8 Dec 01

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, Grav CMS is vulnerable to a Server-Side Template Injection (S

CVE-2024-28119 HIGH POC
8.8 Mar 21

Grav is an open-source, flat-file content management system. Rated high severity (CVSS 8.8), this vulnerability is remot

CVE-2024-28118 HIGH POC
8.8 Mar 21

Grav is an open-source, flat-file content management system. Rated high severity (CVSS 8.8), this vulnerability is remot

CVE-2024-28117 HIGH POC
8.8 Mar 21

Grav is an open-source, flat-file content management system. Rated high severity (CVSS 8.8), this vulnerability is remot

CVE-2024-28116 HIGH POC
8.8 Mar 21

Grav is an open-source, flat-file content management system. Rated high severity (CVSS 8.8), this vulnerability is remot

CVE-2024-27921 HIGH POC
8.8 Mar 21

Grav is an open-source, flat-file content management system. Rated high severity (CVSS 8.8), this vulnerability is remot

Share

EUVD-2026-45083 vulnerability details – vuln.today

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy