dep-xlsx

dep-xlsx is a skill for Claude Code, Codex from HomenShum/NodeBenchAI. It costs 95 tokens per session (1,870 once invoked), scanned A, original, MIT.

A security runbook for using the SheetJS xlsx package, a JavaScript library for reading and writing spreadsheet files.

In plain words
What is it for?
It is for handling xlsx dependency updates and security alerts involving CVE-2024-22363 or CVE-2023-30533, with a pinned CDN tarball and documented alternatives.
Why use it?
It avoids two known high-severity vulnerabilities in the npm-published package by using SheetJS's fixed CDN release instead.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/homenshum/nodebenchai/dep-xlsx
Any agent
npx skills add HomenShum/NodeBenchAI --skill dep-xlsx
Clone the repo
git clone --depth 1 https://github.com/HomenShum/NodeBenchAI

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for dep-xlsx

README.md
[![agentmods](https://agentmods.dev/badge/skills/homenshum/nodebenchai/dep-xlsx.svg)](https://agentmods.dev/skills/homenshum/nodebenchai/dep-xlsx)
Your own site
<a href="https://agentmods.dev/skills/homenshum/nodebenchai/dep-xlsx"><img src="https://agentmods.dev/badge/skills/homenshum/nodebenchai/dep-xlsx.svg" alt="Measured on agentmods" height="20"></a>
Per session 95 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,870 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00095 $0.01870
Opus 5 $0.00048 $0.00935
Sonnet 5 $0.00019 $0.00374
Haiku 4.5 $0.00010 $0.00187

Measured 5d ago against content hash 1663b8686cf6, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

dep-xlsx scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/dep-xlsx/SKILL.md · 132 lines

How it starts

The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.

xlsx (SheetJS) remediation runbook

Last verified

  • Working pin: https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz (held since 2026-04-26)
  • Known-bad: xlsx@^0.18.5 from npm registry (2 HIGH CVEs, no upstream fix)

Why we use a CDN tarball

Two HIGH CVEs against the npm-published xlsx:

  • CVE-2024-22363 — ReDoS in SheetJS
  • CVE-2023-30533 — Prototype Pollution in SheetJS

Neither has a fix on the npm registry. SheetJS moved to publishing fixed releases through their own CDN at cdn.sheetjs.com. The npm version of the package is no longer updated by the maintainers. Their official remediation guidance is to install from the CDN tarball.

Closed by PR #124.

Alternatives evaluated (and rejected)

Option Why rejected
@e965/xlsx (community fork on npm) Published by individual e965 ([email protected]) from e965/sheetjs-npm-publisher. Supply-chain risk: unknown maintainer.
Migrate to exceljs Different API (async streams, 1-indexed cells), 4-8 hours of careful refactoring across 4 files in src/features/documents/, 200KB+ bundle weight increase. No security benefit (CDN already addresses the CVEs).
Migrate to read-excel-file Read-only, doesn't cover the editor/writer paths in SpreadsheetMiniEditor.tsx and SpreadsheetView.tsx. Same migration effort as exceljs but lower coverage.
xlsx-js-style (community fork with styles) Same supply-chain concern as @e965/xlsx.
Wrap usage with input validation Defensive but doesn't make alerts go away.

Recipe (when bumping to a newer SheetJS CDN release)

When SheetJS publishes a new version (check https://cdn.sheetjs.com/):

  1. Update package.json:
    -"xlsx": "https://cdn.sheetjs.com/xlsx-0.20.3/xlsx-0.20.3.tgz",
    +"xlsx": "https://cdn.sheetjs.com/xlsx-0.20.X/xlsx-0.20.X.tgz",
    
  2. npm install
  3. npx tsc --noEmit — should be clean (xlsx API has been stable for years)
  4. npx vite build — must succeed
  5. Manual smoke: open a .xlsx file in the documents preview/editor surfaces and verify it renders + saves correctly

Read the full file on GitHub · 132 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 132 lines · 95 tokens per session scan A 1663b8686cf6

Subscribe to this mod's changes

dep-xlsx is a skill published in the GitHub repository HomenShum/NodeBenchAI (14 stars, last pushed today), licensed MIT. It adds 95 tokens to every session and 1,870 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.