CVE-2021-41122
Bounds check missing for decimal args in Vyper
Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions external functions did not properly validate the bounds of decimal arguments. The can lead to logic errors. This issue has been resolved in version 0.3.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Bounds check missing for decimal args in Vyper
Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions external functions did not properly validate the bounds of decimal arguments. The can lead to logic errors. This issue has been resolved in version 0.3.0.
- Record
CVE-2021-41122- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-682
- Updated
- 2026-11-02
EUVDEUVD-2021-0460
Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions external functions did not properly validate the bounds of decimal arguments. The can lead to logic errors. This issue has been resolved in version 0.3.0.
- Record
EUVD-2021-0460- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-c7pr-343r-5c46
missing clamps for decimal args in external functions
Impact
The following code does not properly validate that its input is in bounds.
@external
def foo(x: decimal) -> decimal:
return x
Patches
0.3.0 / #2447
Workarounds
Don't use decimal args
- Record
GHSA-c7pr-343r-5c46- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-682
- Updated
- 2026-11-02
NVD
Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions external functions did not properly validate the bounds of decimal arguments. The can lead to logic errors. This issue has been resolved in version 0.3.0.
- Record
CVE-2021-41122- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - CVSS 2.0
- 4.0 Medium
AV:N/AC:L/Au:S/C:N/I:P/A:N - Weakness
- CWE-682
- Updated
- 2026-11-02
OSV
Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions external functions did not properly validate the bounds of decimal arguments. The can lead to logic errors. This issue has been resolved in version 0.3.0.
- Record
CVE-2021-41122- CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Updated
- 2026-11-02
OSVGHSA-c7pr-343r-5c46
missing clamps for decimal args in external functions
Impact
The following code does not properly validate that its input is in bounds.
@external
def foo(x: decimal) -> decimal:
return x
Patches
0.3.0 / #2447
Workarounds
Don't use decimal args
- Record
GHSA-c7pr-343r-5c46- CVSS 4.0
- 5.3 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 4.3 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N - Weakness
- CWE-682
- Updated
- 2026-11-02
OSVPYSEC-2021-366 No score
Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions external functions did not properly validate the bounds of decimal arguments. The can lead to logic errors. This issue has been resolved in version 0.3.0.
- Record
PYSEC-2021-366- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
vyperPyPI |
before 0.3.0 | 0.3.0 |
vyperPyPI |
before 0.3.0, plus listed versions 0.1.0b10.1.0b100.1.0b110.1.0b120.1.0b13 Show 28 moreShow less0.1.0b140.1.0b150.1.0b160.1.0b170.1.0b20.1.0b30.1.0b40.1.0b50.1.0b60.1.0b70.1.0b80.1.0b90.2.10.2.100.2.110.2.120.2.130.2.140.2.150.2.160.2.20.2.30.2.40.2.50.2.60.2.70.2.80.2.9 |
0.3.0 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-41122 is a medium vulnerability (CVSS 4.3) in Vyperlang Vyper, published October 5, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.80%, the 56th percentile. Fixed in vyper 0.3.0.