xxe

xxe is a skill for Claude Code from securityfortech/hacking-skills. It costs 116 tokens per session (1,861 once invoked), scanned B, original, no licence file.

A guide to testing XML External Entity injection, a vulnerability in XML parsers that process references to outside files or network locations. XML is a text format often used for data exchange between applications.

In plain words
What is it for?
Use it to review XML parser settings and test applications that accept XML through APIs, file uploads, or document-processing features.
Why use it?
It helps find XML processing that could expose local files, make server-side network requests, or consume excessive resources.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the web plugin — 28 skills shipped together

Good fit Use it to review XML parser settings and test applications that accept XML through APIs, file uploads, or document-processing features.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/securityfortech/hacking-skills/xxe
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.

Any agent
npx skills add securityfortech/hacking-skills --skill xxe
Clone the repo
git clone --depth 1 https://github.com/securityfortech/hacking-skills

Made for: Claude Code.

Or install web, the plugin that ships this one along with the rest of its 28 skills.

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 xxe

README.md
[![agentmods](https://agentmods.dev/badge/skills/securityfortech/hacking-skills/xxe/github.svg)](https://agentmods.dev/skills/securityfortech/hacking-skills/xxe)
Your own site
<a href="https://agentmods.dev/skills/securityfortech/hacking-skills/xxe"><img src="https://agentmods.dev/badge/skills/securityfortech/hacking-skills/xxe/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for xxe

Your own site · 80×15
<a href="https://agentmods.dev/skills/securityfortech/hacking-skills/xxe"><img src="https://agentmods.dev/badge/skills/securityfortech/hacking-skills/xxe.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 116 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,861 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin unknown 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 $0.00116 $0.01861
Opus 5.5 $0.00046 $0.00744
Sonnet 5.5 $0.00023 $0.00372
Haiku 4.5 $0.00012 $0.00186

Measured 2mo ago against content hash eace394204e7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade B, and why

xxe scanned grade B with 1 finding 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 2mo 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.

Cloud metadata endpointmediumServer-side request forgery

One request to 169.254.169.254 can return temporary IAM credentials.

<!DOCTYPE foo [<!ENTITY xxe SYSTEM "http://169.254.169.254/latest/meta-data/">]>

Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.

skills/web/injection/xxe/SKILL.md · 141 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 2mo ago First seen · 141 lines · 116 tokens per session scan B eace394204e7

Subscribe to this mod's changes

xxe is a skill published in the GitHub repository securityfortech/hacking-skills (21 stars, last pushed 7mo ago), with no licence file. It adds 116 tokens to every session and 1,861 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it B with 1 finding (cloud metadata endpoint). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Related

xxe compared with skills from other repositories

xxe next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
xxesecurityfortech/hacking-skillsSkill217mo agononeB116Claude Code
imagegenopenai/codexSkill133kyesterdayApache-2.0A113Codex
playwright-climicrosoft/playwrightSkill99kyesterdayApache-2.0A19Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginnersSkill79k4d agoMITA200Claude Code, Codex
systematic-debuggingobra/superpowersSkill313k3d agoMITA21Claude Code
next-cache-components-adoptionvercel/next.jsSkill143kyesterdayMITA95Claude Code
next-partial-prefetching-adoptionvercel/next.jsSkill143kyesterdayMITA103Claude Code