CVE-2018-18920

HIGHNVD 8.88.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2018-11-21. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 2.9%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Py-EVM v0.2.0-alpha.33 allows attackers to make a vm.execute_bytecode 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."

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
41
EG Risk 41/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity88% × 45%
The EG Score, 8.8 of 10.
Exploitation2.9% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
2.9%
EPSS %ILE
86th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

November 12, 2018

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Aug 17, 2026
Patch available.
Web page

Netta Lab on X: "Netta Labs discovered an Ethereum EVM vulnerability, which could be exploited by hackers. The vulnerability can cause smart contracts can be executed indefinitely without gas being paied." / X

https://twitter.com/NettaLab/status/1060889400102383617
Web page

Invalid values like 100, 0 occurs in Stack during the execution. · Issue #1448 · ethereum/py-evm · GitHub

https://github.com/ethereum/py-evm/issues/1448

Vendor Advisories for CVE-2018-18920(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
pippy-evm—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(2 across 1 ecosystem)
PyPI(2)
PackageVulnerable rangeFix by version rangeDependents
evm-py—
  • every version through 0.2.0-alpha\.33: no fix on record
—
py-evm0.2.0a1 ... 0.2.0a9 (27 versions)
  • every version through 0.2.0a33: no fix on record
  • every version up to 0.2.0a33: fixed in 0.2.0a33
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 27× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 90 of 165 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 10 repeat rows among the latest 100 are merged into the row they repeat. The 75 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-15 16:27 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  2. 2026-10-14 16:27 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  3. 2026-10-13 16:27 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  4. 2026-10-12 20:14 UTCEG score recompute
  5. 2026-10-12 16:28 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  6. 2026-10-12 00:38 UTCEG score recompute
  7. 2026-10-11 13:41 UTCEPSS rescoreEPSS 2.9% · 86th percentile
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  10. 2026-10-08 16:36 UTCEPSS rescoreEPSS 2.9% · 86th percentile
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  14. 2026-10-03 14:21 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  15. 2026-10-01 19:44 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  16. 2026-09-30 14:59 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  17. 2026-09-30 09:58 UTCEG score recompute
  18. 2026-09-28 16:43 UTCOSV refresh
  19. 2026-09-28 13:45 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  20. 2026-09-27 13:40 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  21. 2026-09-26 15:53 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  22. 2026-09-24 13:59 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  23. 2026-09-20 20:10 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  24. 2026-09-19 15:36 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  25. 2026-09-18 19:22 UTCEPSS rescoreEPSS 2.9% · 86th percentile
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  1. 2026-09-17 19:22 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  2. 2026-09-16 05:06 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  3. 2026-09-15 03:05 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  4. 2026-09-13 16:42 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  5. 2026-09-12 14:56 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  6. 2026-09-11 14:47 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  7. 2026-09-11 09:32 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  8. 2026-09-08 21:34 UTCOSV refresh
  9. 2026-09-07 15:57 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  10. 2026-09-06 13:43 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  11. 2026-09-05 15:24 UTCEPSS rescoreEPSS 2.8% · 85th percentile
  12. 2026-09-04 13:56 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  13. 2026-09-04 05:02 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  14. 2026-09-02 14:07 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  15. 2026-09-01 13:49 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  16. 2026-09-01 03:32 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  17. 2026-08-28 21:36 UTCEPSS rescoreEPSS 2.8% · 85th percentile
  18. 2026-08-27 14:21 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  19. 2026-08-26 14:42 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  20. 2026-08-25 13:44 UTCEPSS rescoreEPSS 2.9% · 86th percentile
  21. 2026-08-22 06:37 UTCOSV refresh
  22. 2026-08-21 23:45 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  23. 2026-08-20 22:51 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  24. 2026-08-19 17:00 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  25. 2026-08-18 13:44 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  26. 2026-08-17 13:43 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  27. 2026-08-16 14:51 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  28. 2026-08-16 02:10 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  29. 2026-08-15 01:26 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  30. 2026-08-13 21:56 UTCEPSS rescoreEPSS 2.9% · 85th percentile
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  35. 2026-08-06 13:42 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  36. 2026-08-06 09:45 UTCOSV refresh
  37. 2026-08-05 19:13 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  38. 2026-08-04 15:05 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  39. 2026-08-02 02:23 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  40. 2026-08-01 04:12 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  41. 2026-07-30 16:24 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  42. 2026-07-30 01:27 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  43. 2026-07-28 15:32 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  44. 2026-07-26 14:51 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  45. 2026-07-25 14:14 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  46. 2026-07-24 14:14 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  47. 2026-07-23 14:15 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  48. 2026-07-23 01:34 UTCEG score recompute
  49. 2026-07-22 22:15 UTCEG score recompute
  50. 2026-07-22 14:05 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  51. 2026-07-21 15:22 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  52. 2026-07-21 03:11 UTCOSV refresh
  53. 2026-07-20 17:04 UTCEPSS rescoreEPSS 2.9% · 85th percentile
  54. 2026-07-19 14:28 UTCEPSS rescoreEPSS 2.9% · 85th percentile
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  59. 2026-07-13 22:26 UTCEPSS rescoreEPSS 2.9% · 85th percentile
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  65. 2026-07-07 13:42 UTCEPSS rescoreEPSS 2.9% · 85th percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2018-18920?
CVE-2018-18920 is a high-severity vulnerability; its CVE record was published on November 12, 2018. 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…
When was CVE-2018-18920 made public?
CVE-2018-18920 was made public on November 11, 2018: that is the date its CVE record's CNA, MITRE Corporation, gives for when the vulnerability was made public. The CVE record itself was published on November 12, 2018. EchelonGraph's copy of the record carries a last-modified date of November 21, 2024; the record at its source may have been updated since.
Is CVE-2018-18920 actively exploited?
CVE-2018-18920 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.9% probability of exploitation in the next 30 days (86th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2018-18920?
CVE-2018-18920 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2018-18920?
A fix for CVE-2018-18920 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2018-18920 are linked in the Vendor Advisories panel on this page.

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