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High, CVSS 8.7amended

Py-EVM is vulnerable to arbitrary bytecode injection

CVE-2018-18920GHSA-vqgp-4jgj-5j64

What to do

Vendor response not established. Follow the primary source's mitigation guidance and check back for a fix.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

  • PyPI py-evm

    Affected
    <= 0.2.0a33
    Fixed in
    no fixed version recorded

Sources

Severity and exploitation
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:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2018-18920: 2.93% estimated exploitation activity in the next 30 days; percentile 87.08 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

Py-EVM v0.2.0-alpha.33 allows attackers to make a vm.executebytecode call that triggers computation.stack.values with '"stack": [100, 100, 0]' where b'\x' was expected, resulting in an execution failure because of an invalid opcode. This is reportedly related to "smart contracts can be executed indefinitely without gas being paid."

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-vqgp-4jgj-5j64

  2. Revision 2 · amended ·

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

  3. Revision 1 · created ·

    Published from osv record GHSA-vqgp-4jgj-5j64

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2018-18920

Advisory: Py-EVM is vulnerable to arbitrary bytecode injection
IDs: CVE-2018-18920, GHSA-vqgp-4jgj-5j64
Record: https://patchnext.com/advisories/cve-2018-18920 (revision 3, source checked 26 Oct 2026, 13:42 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 response not established. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI py-evm: affected <= 0.2.0a33

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

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on py-evm.
- 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-vqgp-4jgj-5j64 (OSV record GHSA-vqgp-4jgj-5j64 lists affected ranges: PyPI py-evm >=0 <=0.2.0a33)
- Verified: https://github.com/advisories/GHSA-vqgp-4jgj-5j64 (GitHub-reviewed advisory GHSA-vqgp-4jgj-5j64 lists affected ranges: PyPI py-evm >=0 <=0.2.0a33)

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