CVE-2026-31862: @siteboon/claude-code-ui is Vulnerable to Command Injection via Multiple Parameters

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.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.6%, percentile 48: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 48% of all scored CVEs (low). 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 @siteboon/claudecodeui (npm) <= 1.23.0, fixed in 1.24.0. Check your lockfile, including transitive dependencies.

What it is

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, multiple Git-related API endpoints use execAsync() with string interpolation of user-controlled parameters (file, branch, message, commit), allowing authenticated attackers to execute arbitrary OS commands. This vulnerability is fixed in 1.24.0.

From the GitHub advisory

Summary Multiple Git-related API endpoints use execAsync() with string interpolation of user-controlled parameters (file, branch, message, commit), allowing authenticated attackers to execute arbitrary OS commands.

Details The claudecodeui application provides Git integration through various API endpoints. These endpoints accept user-controlled parameters such as file paths, branch names, commit messages, and commit hashes, which are directly interpolated into shell command strings passed to execAsync().

The application attempts to escape double quotes in some parameters, but this protection is trivially bypassable using other shell metacharacters such as:

Command substitution: $(command) or \command\ Command chaining: ;, &&, || Newlines and other control characters

Affected Endpoints GET /api/git/diff - file parameter GET /api/git/status - file parameter POST /api/git/commit - files array and message parameter POST /api/git/checkout - branch parameter POST /api/git/create-branch - branch parameter GET /api/git/commits - commit hash parameter GET /api/git/commit-diff - commit parameter

Weakness type: CWE-78, CWE-77.

Product: @siteboon/claudecodeui (npm) · Assigned by: GitHub_M · Published: 2026-03-11

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 none, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.59% probability of exploitation activity in the next 30 days; percentile 48.

Timeline

• 2026-03-11 — CVE record published by GitHub_M
• 2026-03-11 — GitHub-reviewed advisory GHSA-f2fc-vc88-6w7q published (critical)
• 2026-03-12 — 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-f2fc-vc88-6w7q github.com
2. CVE.org record CVE-2026-31862 cve.org
3. NVD entry CVE-2026-31862 nvd.nist.gov

Other references from the CVE record and advisory

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

Critical npm advisories · Today’s Security Digest