fuzzing-dictionary SKILL.md skillA
fuzzing-dictionary from trailofbits/skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add trailofbits/skills/fuzzing-dictionary@git:20260826.3deb39ePins git:20260826.3deb39e in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- trailofbits/skills
- Path
plugins/testing-handbook-skills/skills/fuzzing-dictionary/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260826.3deb39e, committed Aug 26, 2026
- First version recorded
- Jan 14, 2026
- Size
- 9,954 bytes
- Repository stars
- 8,043
- License
- CC-BY-SA-4.0
Builds and applies fuzzing dictionaries so a fuzzer can produce the keywords, magic bytes, and tokens a target expects. Covers extracting tokens from source, headers, binaries, and specifications, dictionary syntax, and wiring one into libFuzzer or AFL++. Use when fuzzing a parser, protocol, or file format, when coverage stalls at input validation, or when a target compares against fixed strings.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Fuzzing Dictionary A fuzzing dictionary provides domain-specific tokens to guide the fuzzer toward interesting inputs. Instead of purely random mutations, the fuzzer incorporates known keywords, magic numbers, protocol commands, and format-specific strings that are more likely to reach deeper code paths in parsers, protocol handlers, and file format processors. ## Overview Dictionaries are text files containing quoted strings that represent meaningful tokens for your target. They help fuzzers bypass early validation checks and explore code paths that would be difficult to reach through blind mutation alone. ### Key Concepts | Concept | Description | |---------|-------------| | **Dictionary Entry** | A quoted string (e.g., `"keyword"`) or key-value pair (e.g., `kw="value"`) | | **Hex Escapes** | Byte sequences like `"\xF7\xF8"` for non-printable characters | | **Token Injection** | Fuzzer inserts dictionary entries into generated inputs | | **Cross-Fuzzer Format** | Dictionary files work with libFuzzer, AFL++, and cargo-fuzz | ## When to Apply **Apply this technique when:** - Fuzzing parsers (JSON, XML, config files) …
Read the whole file at its exact version.
How to install
mdr add trailofbits/skills/fuzzing-dictionary@sha256:b71fa7cab36ca466The line at the top of this page pins the label git:20260826.3deb39e, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_62nkisccjkhzjg6g)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Jan 14, 2026 and Aug 26, 2026, about one every 224 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260826.3deb39e latest | 2026-08-26 | 3deb39e | 9,954 B | A | view · diff |
| git:20260114.695119c | 2026-01-14 | 695119c | 9,684 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9954 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
trailofbits/skills · 8,043 stars · license CC-BY-SA-4.0 · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_62nkisccjkhzjg6g GET https://markdownregistry.com/api/v1/resolve?ref=trailofbits/skills/fuzzing-dictionary GET https://markdownregistry.com/api/v1/blob/b71fa7cab36ca466647123efa07c665c1968661f6d5060d9ac0cbb7f7599f7e0
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
More from trailofbits/skills
Every file in trailofbits/skills