libafl
8 findings (4 critical, 4 low), mainly command injection, data exfiltration, policy violation. Most recent scan 2026-02-08.
This LibAFL fuzzing skill is SAFE for use. The skill provides educational documentation about LibAFL, a modular fuzzing library, with installation instructions and usage guidance. No executable scripts are included, and the instruction content is purely informational. The skill does not attempt prompt injection, data exfiltration, command injection, or any other malicious behavior. The identified issues are minor: missing optional metadata fields, truncated instruction content, and references to non-existent Python files. These are documentation quality issues rather than security threats. The skill appears to be an incomplete or work-in-progress documentation resource rather than a functional executable skill.
Scanner's overall assessment (LLM analyzer)
Second scanner: NVIDIA SkillSpector
Independent static run, no language model, over the same files as the Cisco scan above. How the two scanners compare across the whole corpus: Two scanners, one corpus.
What this skill does
LibAFL is a modular fuzzing library for building custom fuzzers. Use for advanced fuzzing needs, custom mutators, or non-standard fuzzing targets.
- Package
- 1 file, 17 KB
- SKILL.md
- 1885 words, 12+ sections
- Code
- None. Instructions only.
SKILL.md covers: LibAFL · When to Use · Quick Start · Installation · Prerequisites · Linux/macOS · Verification · Should produce libFuzzer.a · Writing a Harness · Usage Modes · 1. libFuzzer Drop-in Replacement · 2. Custom Fuzzer as Rust Library
Findings
CRITICAL INJECTION ATTACK detected by YARA Command Injectionstatic
Detects command injection patterns in agent skills: shell operators, system commands, and network tools: wget https://apt.llvm.org/llvm.sh
SKILL.md:62
wget https://apt.llvm.org/llvm.shCRITICAL INJECTION ATTACK detected by YARA Command Injectionstatic
Detects command injection patterns in agent skills: shell operators, system commands, and network tools: curl -O
SKILL.md:512
curl -O https://raw.githubusercontent.com/glennrp/libpng/f8e5fa92b0e37ab597616f554bee254157998227/contrib/oss-fuzz/libpng_read_fuzzer.ccCRITICAL INJECTION ATTACK detected by YARA Command Injectionstatic
Detects command injection patterns in agent skills: shell operators, system commands, and network tools: curl -o
SKILL.md:523
curl -o seeds/input.png https://raw.githubusercontent.com/glennrp/libpng/acfd50ae0ba3198ad734e5d4dec2b05341e50924/contrib/pngsuite/iftp1n3p08.pngCRITICAL INJECTION ATTACK detected by YARA Command Injectionstatic
Detects command injection patterns in agent skills: shell operators, system commands, and network tools: curl -O
SKILL.md:528
curl -O https://raw.githubusercontent.com/glennrp/libpng/2fff013a6935967960a5ae626fc21432807933dd/contrib/oss-fuzz/png.dictLOW Skill does not specify a license Policy Violationstatic
Skill manifest does not include a 'license' field. Specifying a license helps users understand usage terms.
SKILL.md
LOW Missing Optional Metadata Fields Data Exfiltrationllm
The skill manifest is missing optional metadata fields including 'license', 'compatibility', and 'allowed-tools'. While these fields are optional per the agent skills specification, their absence reduces transparency about the skill's behavior and restrictions.
SKILL.md
YAML manifest shows: license: Not specified, compatibility: Not specified, allowed-tools: Not specifiedLOW Incomplete Instruction Content Social Engineeringllm
The instruction body appears to be truncated mid-sentence ('Use LibAFL as a replacement for libFuzzer with existing h'). This could lead to confusion or incomplete guidance for users attempting to use the skill.
Last line of instruction body: 'Use LibAFL as a replacement for libFuzzer with existing h' - appears cut offLOW Referenced Files Not Found Data Exfiltrationllm
The skill references two Python files ('the.py' and 'this.py') that are not present in the skill package. These appear to be placeholder or incorrectly referenced files that could cause confusion or errors if the skill attempts to use them.
Referenced files: the.py, this.py - both marked as 'not found'What is in the package
| File | Kind | Size |
|---|---|---|
SKILL.md | doc | 17 KB |
External hosts referenced
github.com raw.githubusercontent.com aflplus.plus apt.llvm.org docs.rs downloads.sourceforge.net sh.rustup.rs
Hostnames that appear in the skill's files. Referencing a host is not a finding; compare against the findings above and the skill's stated purpose.
Environment variables referenced
FUZZER_CARGO_DIR
Package contents recorded 2026-10-22 at commit a50696e20581. The scan above ran against the version current at scan time; the two can differ if the skill has since been updated.
What we checked
- Static analyzer. Pattern rules over SKILL.md and bundled files: known-bad commands, exfiltration URLs, secrets, obfuscation.
- Llm analyzer. A language model reads the skill and reports intent-level issues the rules cannot express.
- Meta analyzer. A second model pass that validates, deduplicates and re-scores the other analyzers' findings.
What we did not check
- Runtime behaviour. The skill was not executed; findings come from reading its files.
- Anything fetched at install or run time, including remote scripts, package dependencies, and URLs the skill tells the agent to open.
- Content the analyzers cannot read: images, binaries, and some non-English text.
- Known scanner bypass classes. See the methodology and limitations page.
Sources
- Repository: https://github.com/trailofbits/skills
- Raw scan result: plugins-testing-handbook-skills-skills-libafl-scan.json
- Badge for your README:
- Request a re-scan