CVE-2026-42853 Overview
CVE-2026-42853 is a command injection vulnerability in the @apostrophecms/cli package, affecting all versions up to and including 3.6.0. The flaw exists in the apos create command, which embeds user-supplied password prompt input directly into a shell command without sanitization or escaping. An attacker who can influence the prompt input can execute arbitrary operating system commands on the host running the CLI. ApostropheCMS is an open-source Node.js content management system widely used for building structured websites. As of publication, no patched versions are available.
Critical Impact
Local attackers can execute arbitrary commands on the host system through unsanitized input to the apos create password prompt, leading to full compromise of confidentiality, integrity, and availability.
Affected Products
- ApostropheCMS @apostrophecms/cli package versions through 3.6.0
- Node.js environments running the apos create command
- Developer workstations and CI/CD systems using the ApostropheCMS CLI
Discovery Timeline
- 2026-06-12 - CVE-2026-42853 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2026-42853
Vulnerability Analysis
The vulnerability is classified as OS Command Injection [CWE-78]. The apos create command in @apostrophecms/cli constructs a shell command string that includes the password value provided through an interactive prompt. Because the input is concatenated directly into the command, shell metacharacters such as ;, &&, |, and backticks retain their special meaning when the command executes.
An attacker who controls the value entered at the password prompt can append arbitrary shell syntax. The injected commands execute with the privileges of the user running the CLI. On developer workstations this typically equates to full user-level access, including the ability to read source code, exfiltrate credentials, or pivot into connected services.
The attack requires local access and user interaction, which limits remote exploitation. However, the vulnerability becomes relevant in shared environments, scripted automation, or scenarios where prompt input is sourced from untrusted files or pipelines.
Root Cause
The root cause is direct string concatenation of untrusted input into a shell command. The CLI does not use safe APIs such as child_process.execFile with an argument array, nor does it apply shell-escaping to the password value before invoking the underlying shell.
Attack Vector
Exploitation requires a user to run apos create and supply attacker-influenced input at the password prompt. The malicious input contains shell metacharacters followed by arbitrary commands. When the CLI invokes the shell, the injected commands execute alongside the intended command. See the GitHub Security Advisory for technical details.
Detection Methods for CVE-2026-42853
Indicators of Compromise
- Unexpected child processes spawned by node or the apos CLI binary, such as sh, bash, curl, or wget
- Outbound network connections initiated from a shell session launched during apos create
- New files written to user home directories or temporary paths immediately after running the CLI
- Shell history entries containing apos create invocations with unusual prompt inputs
Detection Strategies
- Monitor process trees for apos or node parent processes spawning unexpected shell interpreters or network utilities
- Inspect command-line arguments for shell metacharacters in arguments passed to child_process.exec-style calls
- Audit CI/CD logs where the ApostropheCMS CLI is invoked non-interactively with scripted password input
Monitoring Recommendations
- Enable process execution logging on developer workstations and build agents that use the ApostropheCMS CLI
- Alert on anomalous outbound connections originating from interactive developer sessions
- Track installation and version metadata for the @apostrophecms/cli package across managed endpoints
How to Mitigate CVE-2026-42853
Immediate Actions Required
- Avoid running apos create until a patched release is available, particularly in scripted or shared environments
- Restrict use of the CLI to trusted operators on isolated workstations
- Treat any password value supplied to the prompt as a potential command injection vector and review for shell metacharacters
Patch Information
As of publication, no patched versions of @apostrophecms/cli are available. Track the ApostropheCMS GitHub Security Advisory GHSA-hcwq-x9fw-8cfq for release updates and apply the fixed version when published.
Workarounds
- Run apos create only in ephemeral or containerized environments to limit the blast radius of injected commands
- Manually type passwords at the prompt and avoid pasting values sourced from untrusted documents or repositories
- Replace CLI-based project scaffolding with manual project setup until a fix is released
- Apply least-privilege principles to the user account executing the CLI to reduce potential post-exploitation impact
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
