Vyper's extract32 can ready dirty memory

Exploitation

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

CVSS

3.7 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

EPSS

• CVE-2024-24564: 0.56% estimated exploitation activity in the next 30 days; percentile 46.99 (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.

Summary When using the built-in extract32(b, start), if the start index provided has for side effect to update b, the byte array to extract 32 bytes from, it could be that some dirty memory is read and returned by extract32. As of v0.4.0 (specifically, commit https://github.com/vyperlang/vyper/commit/3d9c537142fb99b2672f21e2057f5f202cde194f), the compiler will panic instead of generating bytecode. Details Before evaluating start, the function Extract32.buildIR caches only: - The pointer in memory/storage to b: https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L916-L918 - The length of b: https://github.com/vyperlang/vyper/blob/10564dcc37756f3d3684b7a91fd8f4325a38c4d8/vyper/builtins/functions.py#L920-L922 but do not cache the actual content of b. This means that if the evaluation of start changes b's content and length, an outdated length will be used with the new content when extracting 32 bytes from b. PoC Calling the…

Published by the source

26 Feb 2024, 20:11 UTC

Last modified by the source

10 Jun 2026, 17:14 UTC

Source last checked

26 Oct 2026, 13:37 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-4hwq-4cpm-8vmx

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-4hwq-4cpm-8vmx

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# Patch Next advisory brief: CVE-2024-24564

Advisory: Vyper's `extract32` can ready dirty memory
IDs: CVE-2024-24564, GHSA-4hwq-4cpm-8vmx
Record: https://patchnext.com/advisories/cve-2024-24564 (revision 2, source checked 26 Oct 2026, 13:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 3.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: vyper 0.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI vyper: affected <= 0.3.10; fixed in 0.4.0

## 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-4hwq-4cpm-8vmx (OSV record GHSA-4hwq-4cpm-8vmx lists affected ranges: PyPI vyper >=0 <0.4.0 (fixed))
- Verified: https://github.com/advisories/GHSA-4hwq-4cpm-8vmx (GitHub-reviewed advisory GHSA-4hwq-4cpm-8vmx lists affected ranges: PyPI vyper >=0 <=0.3.10)

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