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GHSA-4v9q-cgpw-cf38
No affected components available
Impact
when a calling an external contract with no return value, the contract address could be evaluated twice. this is usually only an efficiency problem, but if evaluation of the contract address has side effects, it could result in double evaluation of the side effects.
in the following example, Foo(msg.sender).bar() is the contract address for the following call (to .foo()), and could get evaluated twice
interface Foo:
def foo(): nonpayable
def bar() -> address: nonpayable
@external
def do_stuff():
Foo(Foo(msg.sender).bar()).foo()
Patches
6b4d8ff185de071252feaa1c319712b2d6577f8d
Workarounds
assign contract addresses to variables. the above example would change to
@external
def do_stuff():
t: Foo = Foo(msg.sender).bar()
t.foo()
References
For more information
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the integrity of the data.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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