# safe6Sec/Fastjson

Fastjson姿势技巧集合

Repository: https://github.com/safe6Sec/Fastjson
Canonical: https://ross.abutalabs.com/products/safe6sec-fastjson
License Family: other
Last push: 2023-10-20T02:50:54+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 1868, "days_push": 1048, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1860, forks 355 (observed 2026-08-28T04:05:45.285714+00:00)

## What it is
A curated collection of Fastjson exploitation techniques, payloads, and fingerprinting tricks for Java JSON deserialization vulnerabilities. It covers identifying whether a target uses Fastjson, distinguishing it from other JSON libraries, and probing library versions.

## Use cases
- detect if a Java service uses fastjson
- fingerprint fastjson version on a target
- find deserialization payloads for fastjson
- distinguish jackson from fastjson in blind responses
- learn fastjson deserialization attack techniques
- reproduce fastjson vulnerabilities across versions

## When to choose
- you are doing authorized penetration testing or security research on Java applications using Fastjson
- you need a reference of version-specific Fastjson payloads and detection methods

## When to avoid
- you need a JSON parsing library for your own application - use the official Fastjson or Jackson instead
- you want a scanning tool rather than a manual payload reference
- your use of these techniques is not authorized by the target's owner

## Facets
- artifact type: learning-resource
- maturity: active
- function: security, penetration-testing, vulnerability-scanning, developer-tools
- domain: security, penetration-testing, developer-tools, apis
- platform: cross-platform, cli
- tags: fastjson, java-deserialization, payload-cheatsheet, rce, json-parsing, exploitation-techniques, security-notes

## Member repositories
- safe6Sec/Fastjson (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:05:45.285714+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:15:55.832992+00:00, confidence not recorded.
  - readme: https://github.com/safe6Sec/Fastjson (fetched 2026-08-28T04:05:45.285714+00:00, sha cc4c5c7e98f8)
- Data as of 2026-08-30T08:39:29.467469+00:00.