GHSA-x2c2-q32w-4w6m
MEDIUMVyper's raw_call `value=` kwargs not disabled for static and delegate calls
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.
Blast Radius
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Description
Summary
Vyper compiler allows passing a value in builtin raw_call even if the call is a delegatecall or a staticcall. But in the context of delegatecall and staticcall the handling of value is not possible due to the semantics of the respective opcodes, and vyper will silently ignore the value= argument.
A contract search was performed and no vulnerable contracts were found in production.
Details
The IR for raw_call is built in the RawCall class:
https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/builtins/functions.py#L1100
However, the compiler doesn't validate that if either delegatecall or staticall are provided as kwargs, that value wasn't set. For example, the following compiles without errors:
raw_call(self, call_data2, max_outsize=255, is_delegate_call=True, value=msg.value/2)
Impact
If the semantics of the EVM are unknown to the developer, he could suspect that by specifying the value kwarg, exactly the given amount will be sent along to the target. However in fact, no value will be sent.
Here is an example of an potentially problematic implementation of multicall utilizing the raw_call built-in:
value_accumulator: uint256 = empty(uint256)
results: DynArray[Result, max_value(uint8)] = []
return_data: Bytes[max_value(uint8)] = b""
success: bool = empty(bool)
for batch in data:
msg_value: uint256 = batch.value
value_accumulator = unsafe_add(value_accumulator, msg_value)
if (batch.allow_failure == False):
return_data = raw_call(self, batch.call_data, max_outsize=255, value=msg_value, is_delegate_call=True)
success = True
results.append(Result({success: success, return_data: return_data}))
else:
success, return_data = \
raw_call(self, batch.call_data, max_outsize=255, value=msg_value, is_delegate_call=True, revert_on_failure=False)
results.append(Result({success: success, return_data: return_data}))
assert msg.value == value_accumulator, "Multicall: value mismatch"
return results
Patches
Fixed in https://github.com/vyperlang/vyper/pull/3755
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
References
Are there any links users can visit to find out more?
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | vyper | all versions | 0.4.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vyper. 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 vyper to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x2c2-q32w-4w6m 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-x2c2-q32w-4w6m 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-x2c2-q32w-4w6m. 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-x2c2-q32w-4w6m in your dependencies?
O3 detects GHSA-x2c2-q32w-4w6m across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.