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NVD / CVE Program· CNA GitHub_M

CVE-2025-66299: Security Sandbox Bypass with SSTI (Server Side Template Injection) in the Grav CMS

Noroxi assessment

Priority: Monitor (action score 35/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.60% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: getgrav grav 1.8.0-beta.27.

Low priority for now. Upgrade to getgrav grav 1.8.0-beta.27 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Grav is a file-based Web platform. Prior to 1.8.0-beta.27, Grav CMS is vulnerable to a Server-Side Template Injection (SSTI) that allows any authenticated user with editor permissions to execute arbitrary code on the remote server, bypassing the existing security sandbox. Since the security sandbox does not fully protect the Twig object, it is possible to interact with it (e.g., call methods, read/write attributes) through maliciously crafted Twig template directives injected into a web page. This allows an authenticated editor to add arbitrary functions to the Twig attribute system.twig.safe_filters, effectively bypassing the Grav CMS sandbox. This vulnerability is fixed in 1.8.0-beta.27.

HighCVSS 8.8 · v3.1—No exploit Fix available
Published
Dec 1, 2025
Updated
Sep 25, 2026
EPSS
0.6% · 49th percentile

Report tools

JSON

Action score

35

Monitor

Low priority for now.

CVSS
35 / 40 · 8.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
8.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
getgravgrav

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • getgrav gravbefore 1.8.0
  • getgrav grav1.8.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • getgrav grav

    • < 1.8.0-beta.27affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagistgetgrav/gravbefore 1.8.0-beta.271.8.0-beta.27

Same product

getgrav: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-50286A Remote Code Execution (RCE) vulnerability in Grav CMS v1.7.48 allows an authenticated admin to upload a malicious plugin via the /admin/to
    60This week
  • CVE-2024-27921Grav File Upload Path Traversal vulnerability
    53Plan
  • CVE-2025-66301Grav ihas Broken Access Control which allows an Editor to modify the page's YAML Frontmatter to alter form processing actions
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-66297Dec 1, 2025 · Grav vulnerable to Privilege Escalation and Authenticated Remote Code Execution via Twig Injection
    29Monitor
  • ← EarlierCVE-2025-66298Dec 1, 2025 · Grav is vulnerable to Server-Side Template Injection (SSTI) via Forms
    30Monitor
  • Later →CVE-2025-66300Dec 1, 2025 · Grav is vulnerable to Arbitrary File Read
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
getgrav grav1.8.0-beta.27 · descriptionVendor (CNA)
Packagist:getgrav/grav1.8.0-beta.27Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2025-662940 days apartGrav is vulnerable to RCE via SSTI through Twig Sandbox Bypass
    40Plan
  • CVE-2026-65008232 days apartGrav before 2.0.7 Remote Code Execution via Blueprint dynamicData
    38Monitor
  • CVE-2026-42607161 days apartGrav: Remote Code Execution (RCE) via Malicious Plugin ZIP Upload in Direct Install Feature
    37Monitor
  • CVE-2026-75827260 days apartGrav before 2.0.15 Arbitrary File Write via error_log
    37Monitor
  • CVE-2026-58655226 days apartGrav Flex Objects - Server-Side Template Injection via Dynamic Titles
    34Monitor
  • CVE-2026-69088245 days apartGrav CMS 2.0.7 through 2.0.10 Arbitrary Method Invocation via Blueprint
    34Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-94 · Improper Control of Generation of Code ('Code Injection')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records