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CVE-2022-29255

Multiple evaluation of contract address in call in vyper

8.2 HighFix available

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions prior to 0.3.4 when a calling an external contract with no return value, the contract address (including side effects) could be evaluated twice. This may result in incorrect outcomes for contracts. This issue has been addressed in v0.3.4.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
Low

Exploit likelihood

1.35%Up 0.5 points since Jun 7, 2022
90%50%10%1%

What each source reports

CVE List Score used 8.2

Multiple evaluation of contract address in call in vyper

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions prior to 0.3.4 when a calling an external contract with no return value, the contract address (including side effects) could be evaluated twice. This may result in incorrect outcomes for contracts. This issue has been addressed in v0.3.4.

Record
CVE-2022-29255
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Weakness
CWE-670
Updated
2026-11-02
EUVDEUVD-2022-0356 8.2

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions prior to 0.3.4 when a calling an external contract with no return value, the contract address (including side effects) could be evaluated twice. This may result in incorrect outcomes for contracts. This issue has been addressed in v0.3.4.

Record
EUVD-2022-0356
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Updated
2026-11-02
GitHub AdvisoriesGHSA-4v9q-cgpw-cf38 8.7

Multiple evaluation of contract address in call in vyper

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

Record
GHSA-4v9q-cgpw-cf38
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-670
Updated
2026-11-02
NVD 8.2

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions prior to 0.3.4 when a calling an external contract with no return value, the contract address (including side effects) could be evaluated twice. This may result in incorrect outcomes for contracts. This issue has been addressed in v0.3.4.

Record
CVE-2022-29255
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness
CWE-670
Updated
2026-11-02
OSV 8.2

Multiple evaluation of contract address in call in vyper

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions prior to 0.3.4 when a calling an external contract with no return value, the contract address (including side effects) could be evaluated twice. This may result in incorrect outcomes for contracts. This issue has been addressed in v0.3.4.

Record
CVE-2022-29255
CVSS 3.1
8.2 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L
Weakness
CWE-670
Updated
2026-11-02
OSVGHSA-4v9q-cgpw-cf38 8.7

Multiple evaluation of contract address in call in vyper

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

Record
GHSA-4v9q-cgpw-cf38
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-670
Updated
2026-11-02
OSVPYSEC-2022-43053 7.5

Vyper is a Pythonic Smart Contract Language for the ethereum virtual machine. In versions prior to 0.3.4 when a calling an external contract with no return value, the contract address (including side effects) could be evaluated twice. This may result in incorrect outcomes for contracts. This issue has been addressed in v0.3.4.

Record
PYSEC-2022-43053
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
vyper
PyPI
 before 0.3.4
0.3.4
vyper
PyPI
 before 0.3.4, plus listed versions
0.1.0b10.1.0b100.1.0b110.1.0b120.1.0b13
Show 32 moreShow less
0.1.0b140.1.0b150.1.0b160.1.0b170.1.0b20.1.0b30.1.0b40.1.0b50.1.0b60.1.0b70.1.0b80.1.0b90.2.10.2.100.2.110.2.120.2.130.2.140.2.150.2.160.2.20.2.30.2.40.2.50.2.60.2.70.2.80.2.90.3.00.3.10.3.20.3.3
0.3.4

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2022-29255 is a high vulnerability (CVSS 8.2) in Vyperlang Vyper, published June 6, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.35%, the 71st percentile. Fixed in vyper 0.3.4.

References

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