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Grav CMS CVE-2026-100668

| EUVDEUVD-2026-87762 HIGH
Information Exposure (CWE-200)
2026-09-26 VulnCheck GHSA-g565-6qmq-w49v
7.1
CVSS 4.0 · Vendor: VulnCheck
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Obtain Twig-authoring account on Grav 2.0.x
  2. Delivery
    Store `grav|array` payload in page content
  3. Exploit
    Sandbox-guardless array filter reads raw DI container
  4. Execution
    Cast dumps un-redacted config tree
  5. Persist
    Config with SMTP/OAuth/Redis secrets rendered to anonymous visitors
  6. Impact
    Reuse leaked credentials for lateral movement

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V14 - Data Protection Data exposure prevention
MITRE ATT&CK

2 techniques across 2 tactics: Collection, Discovery

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires an authenticated account with permission to author raw Twig in page content on Grav 2.0.0-2.0.24 with the Twig content sandbox enabled (the sandbox is the very feature being escaped); Grav 1.7 is not affected because it has no Twig content sandbox. Exploitation is limited by this authoring privilege (PR:L, not anonymous write) but is amplified because the stored payload's output is then served to unauthenticated visitors, and no user interaction or non-default configuration is otherwise needed. Effective secret disclosure also depends on the target having populated config secrets (SMTP/OAuth/Redis/proxy) worth harvesting.

Impact

This is a genuine but moderate-priority information-disclosure flaw. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N, score 7.1) is internally consistent with the description: network-reachable, low complexity, requiring low privileges (the ability to author Twig in page content), no user interaction, high confidentiality impact only. No EPSS score, KEV listing, or public POC is present in the input, so there is no signal of active or automated exploitation - exploitation status is 'no public exploit identified at time of analysis.' The realistic risk driver is the privilege model: an attacker must already hold a content-authoring role that permits raw Twig, which is not anonymous access, so this is a privilege-boundary/insider or compromised-editor risk rather than a mass-exploitable unauth bug. The severity is elevated by the payoff - a single grav|array cast dumps the entire un-redacted config tree (SMTP/OAuth secrets, Redis passwords, proxy URLs, plugin credentials) and, because the payload is stored in page content, the leaked secrets are then rendered to anonymous site visitors, effectively laundering the disclosure to the public and enabling lateral movement into the referenced external services. No conflicting signals: CVSS network vector matches the description's web-content delivery. Missing data: no EPSS/KEV/POC (absence, not error).

Exploit ScenarioDerived

An attacker who holds a Grav content-authoring account with Twig privileges (or who has compromised such an account) inserts {{ grav|array|array }} into a page. When the page renders, Grav evaluates the array filter without the sandbox guard, dumping the DI container's private $values including the full un-redacted configuration, which is then displayed to any anonymous visitor loading the page - exposing SMTP, OAuth, Redis, and proxy credentials. No public exploit code is identified, but the payload is a trivial one-line Twig expression.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 26, 2026

An authenticated user who can author raw Twig in page content on Grav CMS 2.0.0 through 2.0.24 can escape the Twig content sandbox and read the site's entire configuration tree, exposing plugin credentials, SMTP and OAuth secrets, Redis passwords, proxy URLs, and the security.* subtree that the sandbox's redaction is designed to hide. The escape works because the array filter and its function form are allowlisted in the sandbox without the needs_is_sandboxed guard carried by print_r, vardump, json_encode, yaml_encode and string, and its implementation calls toArray() or an (array) cast without consulting the sandbox method allowlist, so grav|array unwraps the raw Pimple dependency-injection container and its private $values. Because the payload is stored in page content, the disclosed configuration is rendered to unauthenticated visitors; exploitation requires the authoring privilege (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N) and no public exploit was identified at time of analysis. Grav 1.7 is not affected because it has no Twig content sandbox, and the issue is fixed in Grav 2.0.25.

RemediationAI

Vendor-released patch: upgrade to Grav 2.0.25 or later, which is the fixed version per the advisory GHSA-59qm-58v5-gvc5. Where an immediate upgrade is not possible, the most effective compensating control is to remove the array filter and array function from the Twig sandbox allowlist (via a small custom plugin or an override of the sandbox configuration) so that grav|array can no longer be evaluated; the trade-off is that any legitimate page content relying on that filter will break. Restricting the authoring privilege so that only fully trusted administrators can write raw Twig in page content reduces exposure, at the cost of limiting delegated content workflows, and disabling Twig processing in page content entirely removes the attack surface while disabling dynamic page features site-wide. Because the payload is stored in page content and its output is served to anonymous visitors, also scan existing pages for uses of the array filter or function, and treat any exposure window as a credential compromise: rotate all secrets held in configuration, including SMTP and OAuth credentials, Redis passwords, and proxy URLs, and migrate remaining secrets out of flat-file configuration into environment variables. Rotating credentials has operational impact on dependent services but is warranted if the sandbox was reachable by a non-administrative author, since the security.* configuration subtree was among the data disclosed.

Affected VersionsENISA

grav 0 <2.0.25

Affected Packages

euvd grav fix: 2.0.25

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Grav is a flat-file PHP CMS that renders page content through Twig; version 2.x ships a Twig content sandbox (an allowlist-based Twig_Sandbox_Extension configuration) intended to let users author Twig in page content while blocking access to application internals. This is a CWE-200 information-exposure flaw rooted in an incomplete sandbox allowlist: the array filter and its identical function form are on the allowlist but, unlike print_r, vardump, json_encode, yaml_encode and string, are registered without the needs_is_sandboxed guard, so the sandbox check is never invoked for them. Their implementation then converts the value via toArray() or an (array) PHP cast without consulting the sandbox method allowlist, letting a crafted template dereference protected/private state. The exposed object is the grav Twig global, which is the raw Pimple-based dependency-injection container rather than a redacted proxy; grav|array reveals the private $values array containing service instances, including the un-redacted Config service, and a second cast expands the whole configuration tree. Affected CPE is cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:* mapped to Grav 2.x, with ENISA EUVD listing the vulnerable range as grav 0 < 2.0.25.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 7.1 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 6.5 MEDIUM

Network-delivered stored Twig requires a low-privileged authoring account (PR:L), no interaction, and yields full config confidentiality loss with no integrity or availability impact; scope kept U as the disclosure is of the vulnerable app's own config.

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

Primary rating from Vendor (VulnCheck).

CVSS VectorVendor: VulnCheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

2
Patch available
Sep 26, 2026 - 14:02 EUVD
CVE Published
Sep 26, 2026 - 13:23 cve.org
HIGH 7.1

DescriptionCVE.org

Grav 2.0.0 through 2.0.24 contain a Twig content sandbox escape. The array filter (and its identical function form) is on the sandbox allowlist but is registered without the needs_is_sandboxed guard that print_r, vardump, json_encode, yaml_encode and string carry, and its implementation calls toArray() - or falls back to an (array) cast - without consulting the sandbox method allowlist. Because the grav Twig global is the raw Pimple-based dependency injection container, a user who can author Twig in page content can evaluate grav|array to read the container's private $values array, including the un-redacted Config service; a second array cast returns the entire configuration tree, disclosing plugin credentials, SMTP and OAuth secrets, Redis passwords, proxy URLs and the security.* subtree that the sandbox's redaction is meant to hide. Because the payload is stored in page content, the disclosed configuration is rendered to anonymous visitors. Grav 1.7 is not affected as it has no Twig content sandbox. Fixed in Grav 2.0.25.

Technical POC Analysis

CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor), exploited through a Twig content sandbox escape in Grav core.

Full technical POC analysis - root cause, step-by-step exploitation and patch breakdown - is part of the Pro and Business plans.

Executive ViewAI

Why It Matters

Grav CMS versions 2.0.0 through 2.0.24 contain a sandbox-escape flaw that allows any user with page-authoring privileges to extract the site's complete configuration tree, including plugin credentials, SMTP and OAuth secrets, Redis passwords, and proxy URLs. Because the malicious payload is stored in page content and rendered to site visitors, secrets intended to remain private can be disclosed to unauthenticated parties, turning a routine content-authoring role into a broad credential-exposure risk. Leadership should treat this as a high-priority exposure event because the leaked secrets frequently grant access to adjacent systems such as mail relays, caches, and authentication providers.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 82% exploitable
Prevalence
Low
Grav is a niche PHP flat-file CMS, limited enterprise footprint
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Partial

Priority Score

36
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +36
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

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