CVE-2024-32647 — vyper
MEDIUMCVE-2024-32647 is a medium-severity (CVSS 5.3) CWE-95 vulnerability in vyper. A fix is available for vyper — see the affected versions and patch details below.
vyper performs double eval of raw_args in create_from_blueprint
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.
Exploitation and automatability from CISA’s SSVC triage for CVE-2024-32647.
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
CVE-2024-32647 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 377,636 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
vyperReal-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
Using the create_from_blueprint builtin can result in a double eval vulnerability when raw_args=True and the args argument has side-effects.
A contract search was performed and no vulnerable contracts were found in production. In particular, the raw_args variant of create_from_blueprint was not found to be used in production.
Details
It can be seen that the _build_create_IR function of the create_from_blueprint builtin doesn't cache the mentioned args argument to the stack: https://github.com/vyperlang/vyper/blob/cedf7087e68e67c7bfbd47ae95dcb16b81ad2e02/vyper/builtins/functions.py#L1847
As such, it can be evaluated multiple times (instead of retrieving the value from the stack).
PoC
The vulnerability is demonstrated in the following boa test:
src1 = """
c: uint256
"""
deployer = """
created_address: public(address)
deployed: public(uint256)
@external
def get() -> Bytes[32]:
self.deployed += 1
return b''
@external
def create_(target: address):
self.created_address = create_from_blueprint(target, raw_call(self, method_id("get()"), max_outsize=32), raw_args=True, code_offset=3)
"""
Factory = b.loads_partial(src1)
c = Factory.deploy_as_blueprint()
c2 = b.loads(deployer, b'')
c2.create_(c)
c2.deployed()
The output of c2.deployed() is 2 although create_ was called only once and the value was initialized to 0.
Patches
Patched in https://github.com/vyperlang/vyper/pull/3976.
Impact
No vulnerable production contracts were found. Additionally, double evaluation of side-effects should be easily discoverable in client tests. As such, the impact is low.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | vyper | all versions | 0.4.0pip install --upgrade 'vyper==0.4.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vyper, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update vyper to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-32647 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-32647 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2024-32647. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-32647 in your dependencies?
O3 Security finds CVE-2024-32647 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.