security-global-output-encoding

A set of rules for safely encoding untrusted data before placing it into HTML, JavaScript, SQL, URLs, or other output formats. The required encoding depends on where the data is used.

In plain words
What is it for?
Reviewing or guiding code that displays user data, builds links or scripts, or sends values to databases and similar interfaces.
Why use it?
It helps prevent injection attacks, which can happen even when incoming data has been validated.

Cursor rule for Cursor

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 rules/adobedocs/ff-services-docs/security-global-output-encoding
Clone the repo
git clone --depth 1 https://github.com/AdobeDocs/ff-services-docs

Made for: Cursor.

Per session 19 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 978 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 $0.00019 $0.00978
Opus 5 $0.00010 $0.00489
Sonnet 5 $0.00004 $0.00196
Haiku 4.5 $0.00002 $0.00098

Measured 2d ago against content hash c8e418e38ebb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

security-global-output-encoding 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 2d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.cursor/rules/security-global/security-global-output-encoding.mdc · 130 lines

How it starts

The opening of the file, as written. The whole thing — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Output Encoding & Escaping

Output encoding and parameterization are critical controls for stopping injection attacks. Use context-specific encoding whenever untrusted data is rendered, and pair it with parameterized interfaces for SQL, shell, or LDAP operations. This requirement is distinct from input validation.

All violations must include a clear explanation of which rule was triggered and why.

Critical: Output Encoding ≠ Input Validation

Input validation alone does NOT prevent injection attacks.

  • Input Validation: Ensures data is well-formed before entering system
  • Output Encoding: Prevents injection by encoding data for output context

Context-Specific Encoding

Encoding method MUST match output context. Wrong encoding = vulnerability.

1. HTML Context

Inserting into HTML body: Encode & < > " ' /

2. HTML Attribute Context

  • Always quote attributes
  • Use HTML attribute encoding
  • Never use event handlers: onclick, onerror, onload
  • Avoid href with javascript: URLs

3. JavaScript Context

  • Use JSON encoding for data (e.g., JSON.stringify) before inserting untrusted values.
  • When embedding JSON in tags, escape < (\u003c) at minimum, and also escape & (\u0026) and the Unicode line/paragraph separators (\u2028, \u2029) to block script-breakout payloads
  • Prefer with textContent; parse later instead of concatenating data into executable scripts.
  • Avoid inline scripts, event handler attributes, and javascript: URLs for untrusted data.
  • Layer with CSP for defense in depth, but never treat it as a substitute for correct encoding.

4. CSS Context

Avoid entirely - extremely dangerous. If unavoidable: Use CSS hex escaping. Prefer allowlist validation for class names.

5. URL Context

  • Use URL/percent encoding
  • Allowlist protocols: https:, http:, mailto:
  • Block: javascript:, data:, vbscript:

6. SQL Context

PRIMARY defense: Parameterized queries / Prepared statements. Never rely on escaping alone.

Read the full file on GitHub · 130 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. 2d ago First seen · 130 lines · 19 tokens per session scan A c8e418e38ebb

Subscribe to this mod's changes

security-global-output-encoding is a cursor rule published in the GitHub repository AdobeDocs/ff-services-docs (4 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 19 tokens to every session and 978 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 2026-08-31.