CVE-2023-32059

Vyper vulnerable to incorrect ordering of arguments for kwargs passed to internal calls

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?

Internal calls to internal functions with more than 1 default argument are compiled incorrectly. Depending on the number of arguments
provided in the call, the defaults are added not right-to-left, but left-to-right. If the types are incompatible,
typechecking is bypassed. In the bar() function in the following code, self.foo(13) is compiled to
self.foo(13,12) instead of self.foo(13,1337).

@internal
def foo(a:uint256 = 12, b:uint256 = 1337):
    pass

@internal
def bar():
    self.foo(13)

note that at the time of publication, the ability to pass kwargs to internal functions is an undocumented feature that does not seem to be widely used.

CVE-2023-32059 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.3.8); upgrading removes the vulnerable code path.

Kodem intelligence

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patched in c3e68c302aa6e1429946473769dd1232145822ac

1. What is CVE-2023-32059? CVE-2023-32059 is a high-severity security vulnerability in vyper (pip), affecting versions < 0.3.8. It is fixed in 0.3.8.
2. How severe is CVE-2023-32059? CVE-2023-32059 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of vyper are affected by CVE-2023-32059? vyper (pip) versions < 0.3.8 is affected.
4. Is there a fix for CVE-2023-32059? Yes. CVE-2023-32059 is fixed in 0.3.8. Upgrade to this version or later.
5. Is CVE-2023-32059 exploitable, and should I be worried? Whether CVE-2023-32059 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-32059 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-32059? Upgrade vyper to 0.3.8 or later.

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