CVE-2026-27938 in wp-graphql
Summary
by MITRE • 02/26/2026
WPGraphQL provides a GraphQL API for WordPress sites. Prior to version 2.9.1, the `wp-graphql/wp-graphql` repository contains a GitHub Actions workflow (`release.yml`) vulnerable to OS command injection through direct use of `${{ github.event.pull_request.body }}` inside a `run:` shell block. When a pull request from `develop` to `master` is merged, the PR body is injected verbatim into a shell command, allowing arbitrary command execution on the Actions runner. Version 2.9.1 contains a fix for the vulnerability.
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Analysis
by VulDB Data Team • 02/26/2026
The vulnerability identified as CVE-2026-27938 affects WPGraphQL, a popular GraphQL API implementation for WordPress platforms. This security flaw exists within the repository's GitHub Actions workflow configuration specifically in the release.yml file. The vulnerability represents a critical command injection weakness that arises from improper input validation and sanitization within the automated build and release process. The flaw allows attackers to execute arbitrary commands on the Actions runner environment by manipulating the pull request body content, creating a severe security risk for projects relying on automated deployment workflows.
The technical implementation of this vulnerability stems from the direct inclusion of unvalidated user input within shell execution contexts. The workflow configuration uses `${{ github.event.pull_request.body }}` without any sanitization or validation before incorporating it into a shell command execution block. This pattern violates fundamental security principles and creates an environment where malicious actors can inject shell commands through the pull request description field. The vulnerability is particularly dangerous because it operates within the trusted GitHub Actions environment, allowing attackers to execute commands with the privileges of the Actions runner, potentially compromising the entire build infrastructure.
The operational impact of this vulnerability extends beyond simple code injection, creating a potential attack vector for full system compromise within the CI/CD pipeline. When a pull request is merged from develop to master, the automated workflow triggers and executes the malicious commands embedded in the pull request body, potentially allowing attackers to access sensitive deployment credentials, execute unauthorized code, or even gain access to production environments. This vulnerability directly impacts the integrity of the software supply chain and represents a significant risk to organizations relying on automated deployment processes. The attack surface is particularly concerning as it requires no privileged access to the repository itself, only the ability to submit a pull request with malicious content.
This vulnerability maps directly to CWE-78, which describes improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The fix implemented in version 2.9.1 addresses the core issue by properly sanitizing or escaping the pull request body content before incorporating it into shell commands. Organizations should immediately update to version 2.9.1 or later to mitigate this risk, while also implementing additional safeguards such as restricting pull request permissions, validating all automated workflow inputs, and monitoring for suspicious activity in CI/CD environments. The incident highlights the critical importance of input validation in automated systems and demonstrates how seemingly benign configuration elements can create severe security vulnerabilities when not properly secured against injection attacks.