Multiple evaluation of contract address in call in vyper

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N · score source

EPSS

• CVE-2022-29255: 1.35% estimated exploitation activity in the next 30 days; percentile 71.51 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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 Patches 6b4d8ff185de071252feaa1c319712b2d6577f8d Workarounds assign contract addresses to variables. the above example would change to References For more information

Published by the source

6 Jun 2022, 21:23 UTC

Last modified by the source

19 Nov 2024, 16:22 UTC

Source last checked

26 Oct 2026, 13:27 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4v9q-cgpw-cf38

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-4v9q-cgpw-cf38

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# Patch Next advisory brief: CVE-2022-29255

Advisory: Multiple evaluation of contract address in call in vyper
IDs: CVE-2022-29255, GHSA-4v9q-cgpw-cf38
Record: https://patchnext.com/advisories/cve-2022-29255 (revision 3, source checked 26 Oct 2026, 13:27 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: vyper 0.3.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI vyper: affected < 0.3.4; fixed in 0.3.4

## Suggested inspection (read-only)
- `python -m pip show vyper`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on vyper.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-4v9q-cgpw-cf38 (OSV record GHSA-4v9q-cgpw-cf38 lists affected ranges: PyPI vyper >=0 <0.3.4 (fixed))
- Verified: https://github.com/advisories/GHSA-4v9q-cgpw-cf38 (GitHub-reviewed advisory GHSA-4v9q-cgpw-cf38 lists affected ranges: PyPI vyper >=0 <0.3.4)

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