Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Medium severity, published 6 October 2026.
- Which products and versions are affected?
- vyper (PyPI) < 0.2.6; Vyper < 0.2.6.
- Is there a fix for This vulnerability?
- Yes: fixed in 0.2.6. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is This vulnerability attacked?
- It is attacked over the network, in a software library.
- Am I affected?
- Check whether you run vyper (PyPI) or Vyper at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 0.2.6
Technical details
A stack management bug in Vyper's compiler incorrectly assumes all array and struct subtypes occupy exactly 32 bytes when computing stack offsets during function calls. For complex nested types that don't meet this assumption, arguments are placed at wrong stack positions, causing data corruption and incorrect return values. The vulnerability affects internal and external function calls with no special preconditions required.
Affected products
- Vyper Vyper < 0.2.6
Timeline
- 2020-10-10: disclosed
- 2020-10-10: patched