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.
npx skills add ByamB4/find-cve-agent --skill xxegit clone --depth 1 https://github.com/ByamB4/find-cve-agentWrote 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.
[](https://agentmods.dev/skills/byamb4/find-cve-agent/xxe)<a href="https://agentmods.dev/skills/byamb4/find-cve-agent/xxe"><img src="https://agentmods.dev/badge/skills/byamb4/find-cve-agent/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.
<a href="https://agentmods.dev/skills/byamb4/find-cve-agent/xxe"><img src="https://agentmods.dev/badge/skills/byamb4/find-cve-agent/xxe.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00029 | $0.01027 |
| Opus 5 | $0.00015 | $0.00513 |
| Sonnet 5 | $0.00006 | $0.00205 |
| Haiku 4.5 | $0.00003 | $0.00103 |
Grade A, and why
xxe 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 134 lines — stays where its author put it; the contents beside it link to each section on GitHub.
XXE Detection
When to Use
Audit XML processing endpoints, SOAP services, document importers (DOCX/XLSX/SVG), and any code that parses XML from untrusted sources.
Key Distinction from Entity Expansion
- XXE = EXTERNAL entities (
file://,http://) -- reads files or makes HTTP requests - Entity expansion = INTERNAL entity recursion (Billion Laughs) -- memory exhaustion DoS
Both can exist in the same parser, but they are different vulnerabilities.
Process
Step 1: Find XML Parsers
# JavaScript
grep -rn "DOMParser\|XMLParser\|xml2js\|libxmljs\|xmldom\|sax\|saxes" .
# Python
grep -rn "xml\.etree\|lxml\|minidom\|xml\.sax\|defusedxml\|xmltodict" .
# Go
grep -rn "xml\.Decoder\|xml\.Unmarshal\|encoding/xml" .
# Java
grep -rn "DocumentBuilder\|SAXParser\|XMLReader\|TransformerFactory\|SchemaFactory" .
# PHP
grep -rn "simplexml\|DOMDocument\|XMLReader\|xml_parse" .
# Ruby
grep -rn "Nokogiri\|REXML\|Ox\|LibXML" .
Step 2: Check External Entity Configuration
grep -rn "FEATURE_SECURE_PROCESSING\|FEATURE_EXTERNAL_ENTITIES\|FEATURE_GENERAL_ENTITIES" .
grep -rn "resolve_entities\|external_entities\|load_external\|noent\|nonet" .
grep -rn "disallow-doctype-decl\|external-general-entities\|external-parameter-entities" .
grep -rn "XXE\|external.*entity\|doctype" .
Step 3: Check Default Safety
Most modern parsers are SAFE by default. Key exceptions:
| Parser | Default External Entities | Safe? |
|---|---|---|
| xml.etree (Python) | Enabled | UNSAFE |
| xml.sax (Python) | Enabled | UNSAFE |
| lxml (Python) | Disabled | SAFE |
| defusedxml (Python) | Disabled | SAFE |
| encoding/xml (Go) | No entity support | SAFE |
| Nokogiri (Ruby) | Disabled | SAFE |
| REXML (Ruby) | Enabled | UNSAFE |
| libxml2 (C) | Depends on flags | CHECK |
| Java DocumentBuilder | Enabled | UNSAFE |
| PHP simplexml | Depends on libxml2 config | CHECK |
| PHP DOMDocument | Depends on libxml2 config | CHECK |
Step 4: Verify User Input Reaches Parser
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago First seen · 134 lines · 29 tokens per session scan A 0eeb037c1297
xxe is a skill published in the GitHub repository ByamB4/find-cve-agent (48 stars, last pushed 5mo ago), licensed Apache-2.0. It adds 29 tokens to every session and 1,027 once invoked, about $0.0001 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.
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