CVE-2026-42607: Grav Vulnerable to Remote Code Execution (RCE) via Malicious Plugin ZIP Upload in Direct Install Feature

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 2.3%, percentile 83: FIRST’s model estimates a 2.3% chance of exploitation activity in the next 30 days, higher than 83% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
• Needs an account (high (admin)). Exposure depends on who can log in.
• Only applies if your dependency tree includes getgrav/grav (Composer (PHP)) < 2.0.0-beta.2, fixed in 2.0.0-beta.2. Check your lockfile, including transitive dependencies.

What it is

Grav is a file-based Web platform. Prior to 2.0.0-beta.2, an authenticated user with administrative privileges can achieve Remote Code Execution (RCE) by uploading a specially crafted ZIP file through the "Direct Install" tool. While the system attempts to block direct .php file uploads, it fails to inspect the contents of uploaded ZIP archives. Once a malicious plugin is extracted, it can execute arbitrary PHP code or drop a persistent web shell on the server. This vulnerability is fixed in 2.0.0-beta.2.

From the GitHub advisory

Summary An authenticated user with administrative privileges can achieve Remote Code Execution (RCE) by uploading a specially crafted ZIP file through the "Direct Install" tool. While the system attempts to block direct .php file uploads, it fails to inspect the contents of uploaded ZIP archives. Once a malicious plugin is extracted, it can execute arbitrary PHP code or drop a persistent web shell on the server.

Details

The vulnerability exists in the handling of the directInstall task within the Admin plugin and the Grav Package Manager (GPM) core.

- Vulnerable Endpoints: /admin/tools/direct-install - Vulnerable Logic: AdminController.php (lines 1247-1295) and Gpm.php (lines 214-285). - Root Cause: The function Installer::install() (called in Gpm.php:291) extracts the contents of the ZIP file directly into the /user/

plugins/ or /user/themes/ directories without validating the file extensions or the content of the files inside the archive.

Weakness type: CWE-94.

Product: getgrav/grav (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-05-11

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: high (admin)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 2.25% probability of exploitation activity in the next 30 days; percentile 83.

Timeline

• 2026-05-05 — GitHub-reviewed advisory GHSA-w48r-jppp-rcfw published (critical)
• 2026-05-11 — CVE record published by GitHub_M
• 2026-05-12 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-w48r-jppp-rcfw github.com
2. CVE.org record CVE-2026-42607 cve.org
3. NVD entry CVE-2026-42607 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical Composer (PHP) advisories · Today’s Security Digest