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Grav CMS CVE-2026-92917

| EUVDEUVD-2026-81439 HIGH
Information Exposure (CWE-200)
2026-09-17 VulnCheck GHSA-rv7g-323x-h2q2
8.7
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
    Authenticate as page-editor
  2. Delivery
    Create/edit page with Twig processing enabled
  3. Exploit
    Insert {{ config|print_r }} filter
  4. Execution
    Render bypasses unenforced sandbox guard
  5. Impact
    Dump merged Config secrets (SMTP/API/webhook/cache)

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 page-edit rights AND a page with Twig processing enabled on its content - both are prerequisites named in the description. Grav 2.0.0-rc.1 through 2.0.21 only; Grav 1.7 is NOT affected because it ships no Twig content sandbox, and 2.0.22 fixes it by registering the filters with Twig's needs_is_sandboxed flag. The exploit uses the dump/serialize filters (print_r, vardump, json_encode, yaml_encode, string). Limiting factors: attacker must first obtain editor-level access, so this is a privilege-to-secrets escalation rather than an unauthenticated exposure; no user interaction from a victim is needed once the malicious page renders.

Impact

This is a genuine but moderate-priority information-disclosure flaw, not a critical remote-takeover. The vendor CVSS 4.0 vector (8.7) sets PR:N, but the description explicitly requires 'an authenticated user with page-edit rights' - a direct contradiction that materially lowers real risk. The vendor score should read PR:L; my reassessment lands around CVSS 3.1 6.5. Impact is confidentiality-only (VC:H, VI:N, VA:N) with no code execution or data tampering. There is no EPSS score, no CISA KEV listing, and no public POC in the provided data - so no evidence of active or automated exploitation. The realistic threat is a low-privilege editor (or a compromised editor account) escalating access to secrets rather than an unauthenticated internet-wide attack. CONFLICT TO VERIFY: CVSS PR:N vs. description's 'authenticated user with page-edit rights' - treat this as an authenticated flaw, not unauthenticated.

Exploit ScenarioDerived

An attacker who already holds (or has phished/compromised) a Grav account with page-edit rights creates or edits a page with Twig processing enabled and inserts {{ config|print_r }} in the content. When the page renders, print_r reflects the real Config object behind the SandboxConfig facade and bypasses path redaction, dumping the entire merged configuration including SMTP credentials, API tokens, webhook secrets and cache backend passwords. No public exploit code is identified in the provided data, though the technique is trivially reproducible from the advisory.

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 17, 2026

Grav CMS 2.0.0-rc.1 through 2.0.21 discloses its entire merged configuration - including plugin-level secrets such as SMTP credentials, API tokens, webhook secrets and cache backend passwords - to an authenticated user with page-edit rights who renders a dump/serialize filter such as {{ config|print_r }} in page content that has Twig processing enabled. The Twig content sandbox guard introduced in GHSA-mc5q-6hpj-rp7j never fires because GravExtension::assertSandboxDumpSafe() calls SandboxExtension::isSandboxed() without a Source argument, which reports only the global sandbox flag that Grav never enables; this is a privilege-to-secrets escalation rather than an unauthenticated exposure, since editor-level access is a prerequisite. Vendor-released patch: 2.0.22, where the affected filters are registered with Twig's needs_is_sandboxed flag; Grav 1.7 is not affected because it ships no Twig content sandbox, and no public exploit identified at time of analysis.

RemediationAI

Upgrade Grav CMS to 2.0.22, the vendor-released patch that registers the dump/serialize filters with Twig's needs_is_sandboxed flag so assertSandboxDumpSafe() evaluates sandbox state per source; the advisory at https://github.com/getgrav/grav/security/advisories/GHSA-rfr9-7h4p-gx2x documents the fix. Because the exploit prerequisite is an authenticated account with page-edit rights plus a page whose content has Twig processing enabled, interim mitigations are: turn off Twig processing on page content (or on page types authored by lower-trust editors) via the page's Twig processing option, accepting that this disables legitimate Twig templating in content; tighten the page-edit permission so only fully trusted administrators can author or edit Twig-processed pages - note this limits editorial workflow flexibility but removes the required access level; and treat any Grav 2.0.0-rc.1-2.0.21 instance with untrusted editors and plugin secrets as potentially exposed, rotating SMTP passwords, API tokens, webhook secrets and cache backend passwords stored in configuration. No vendor-released patch is missing here, so these controls are stopgaps until the 2.0.22 upgrade can be applied; authentication requirements are authenticated (the assessed vector carries PR:L, and page-edit rights are a documented precondition).

Affected VersionsENISA

grav 2.0.0-rc.1 <2.0.22

Affected Packages

euvd grav fix: 2.0.22

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 CMS that processes page content through Twig, and the affected code path is the interaction between Grav's own GravExtension and Twig's sandbox extension (root cause class: CWE-200, exposure of sensitive information). Grav's guard function assertSandboxDumpSafe() is supposed to restrict the dump/serialize filters (print_r, vardump, json_encode, yaml_encode, string) when running inside a sandboxed environment, but it determines sandbox state by invoking SandboxExtension::isSandboxed() with no Source argument. Without a Source, that method only reflects the global sandbox flag, which Grav never sets, so the guard returns 'safe' unconditionally and the class added by GHSA-mc5q-6hpj-rp7j is inert for page content. The disclosure is amplified by the SandboxConfig facade: print_r operates on the real Config object held in a private property of the facade, so the facade's path redaction is bypassed and the whole merged configuration tree, including plugin secrets, is rendered. The fix in 2.0.22 registers the affected filters with Twig's needs_is_sandboxed flag, which forces correct sandbox state evaluation per source rather than relying on the global flag. The affected component is the Grav core Twig content pipeline, identified by CPE cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:* (EUVD range grav 2.0.0-rc.1 <2.0.22).

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 8.7 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 6.5 MEDIUM

Requires an authenticated page-editor account (PR:L, not PR:N); network-reachable admin/render with low complexity; confidentiality-only secret disclosure, no integrity or availability impact.

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
None
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 17, 2026 - 12:01 EUVD
CVE Published
Sep 17, 2026 - 11:16 cve.org
HIGH 8.7

DescriptionCVE.org

Grav is a flat-file CMS. In versions 2.0.0-rc.1 through 2.0.21, the Twig content sandbox fails to restrict the dump and serialize filters (print_r, vardump, json_encode, yaml_encode, string): GravExtension::assertSandboxDumpSafe() determines sandbox state by calling SandboxExtension::isSandboxed() without a Source argument, which reports only the global sandbox flag that Grav never enables, so the guard added in GHSA-mc5q-6hpj-rp7j never executes. As a result, an authenticated user with page-edit rights can render {{ config|print_r }} in page content with Twig processing enabled and dump Grav's entire merged configuration - print_r reflects the real Config object held in a private property of the SandboxConfig facade, bypassing its path redaction - exposing plugin secrets such as SMTP credentials, API tokens, webhook secrets and cache backend passwords. Grav 1.7 is not affected because it ships no Twig content sandbox. The issue is fixed in 2.0.22, where the affected filters are registered with Twig's needs_is_sandboxed flag.

Technical POC Analysis

Advisory: GHSA-rfr9-7h4p-gx2x (getgrav/grav, Composer).

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-rc.1 through 2.0.21 can expose the platform's full merged configuration-including SMTP credentials, API tokens, webhook secrets, and cache backend passwords-to a user with page-edit permissions. This creates a privilege-to-secrets escalation where editor-level content access can lead to theft of credentials that may enable lateral movement and compromise of connected services. The vendor has released Grav 2.0.22 to correct the issue, and no public exploit identified at time of analysis.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 73% exploitable
Prevalence
Medium
popular open-source flat-file CMS, common but far below WordPress scale
Data Quality
5 sources
Confidence: Medium

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· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
High

Priority Score

44
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +44
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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