hunting-python-unsafe-deserialization SKILL.md skillA
hunting-python-unsafe-deserialization from unboundcompute/security-agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add unboundcompute/security-agent-skills/hunting-python-unsafe-deserialization@git:20260826.c45369bPins git:20260826.c45369b in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- unboundcompute/security-agent-skills
- Path
skills/hunting-python-unsafe-deserialization/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260826.c45369b, committed Aug 26, 2026
- Size
- 8,630 bytes
- Repository stars
- 26
- License
- MIT
Hunt Python deserialization that executes attacker code: untrusted input reaching pickle.loads, an unsafe YAML load, marshal, jsonpickle, dill, or a numpy or pandas loader that unpickles, where the format supports arbitrary object construction through __reduce__ or a tag. Covers pickled data in requests, cookies, caches, message queues, and model or dataframe files, and YAML documents that instantiate arbitrary Python objects. Use when a service loads serialized Python objects it did not…
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
# Hunting Python unsafe deserialization: when loading data calls a function Several Python serialization formats are not data formats at all; they are programs. `pickle` invokes `__reduce__` during load, which names a callable and its arguments and runs them, so a pickled blob can call any importable function on reconstruction. YAML's full loader instantiates arbitrary Python objects from tags. `marshal`, `dill`, `jsonpickle`, and the model and dataframe loaders that wrap pickle inherit the same property. The vulnerability is not a bug in these libraries; it is using them on data an attacker controls. You find it by locating every loader that reconstructs objects rather than parsing data, and asking whether untrusted bytes reach it. ## When to use - A service loads serialized Python objects from a request, a cookie, a cache, a queue, or a file. - The loader in use reconstructs arbitrary objects: pickle, unsafe YAML, marshal, dill, or jsonpickle. - A model, dataframe, or checkpoint file from an untrusted source is loaded through a pickling loader. ## Scope check Test deserialization only against services you own or are authorized to assess, on non-production data. A …
Read the whole file at its exact version.
How to install
mdr add unboundcompute/security-agent-skills/hunting-python-unsafe-deserialization@sha256:49ad7c153f43796eThe line at the top of this page pins the label git:20260826.c45369b, 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_ecffjw5us7xzsamb)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Aug 26, 2026.
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 (8630 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
unboundcompute/security-agent-skills · 26 stars · license MIT · pushed 2026-09-08 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_ecffjw5us7xzsamb GET https://markdownregistry.com/api/v1/resolve?ref=unboundcompute/security-agent-skills/hunting-python-unsafe-deserialization GET https://markdownregistry.com/api/v1/blob/49ad7c153f43796e8f345e464bd07e7ca0cc6c5d7795ac9b1c621cfa96a1275d
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.