CVE-2018-4121

HIGHNVD 8.88.8—
EchelonGraph scoreMEDIUM confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-14. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
8.8EG
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • Public exploit code is available (Exploit-DB (verified), epss top5pct, public exploit)
CISA-KEV: Not listedEPSS PROB: 13%CVSS: 8.8Exploit: Exploit-DB (verified) · epss top5pct · public exploitExposed services: Not assessed

A fix is available — apply it.

An issue was discovered in certain Apple products. iOS before 11.3 is affected. Safari before 11.1 is affected. iCloud before 7.4 on Windows is affected. iTunes before 12.7.4 on Windows is affected. tvOS before 11.3 is affected. watchOS before 4.3 is affected. The issue involves the "WebKit" component. It allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via a crafted web site.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
70
EG Risk 70/100CISA SSVC

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
Severity88% × 45%
Exploitation65% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
13%
EPSS %ILE
96th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (EG-KEV: weaponized) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

April 3, 2018

Last Modified

November 21, 2024

Advisory Details (10)

Auto-updated Aug 17, 2026
🔬 Proof of concept available. Patch available.
generic🟡 PoC Available

WebKit - WebAssembly Parsing Does not Correctly Check Section Order - Multiple dos Exploit

https://www.exploit-db.com/exploits/44427/
generic

About the security content of tvOS 11.3 - Apple Support

https://support.apple.com/HT208698
generic

About the security content of iCloud for Windows 7.4 - Apple Support

https://support.apple.com/HT208697
generic

About the security content of watchOS 4.3 - Apple Support

https://support.apple.com/HT208696
generic

About the security content of Safari 11.1 - Apple Support

https://support.apple.com/HT208695
generic

About the security content of iTunes 12.7.4 for Windows - Apple Support

https://support.apple.com/HT208694
generic

About the security content of iOS 11.3 - Apple Support

https://support.apple.com/HT208693
generic

WebkitGTK+: Multiple vulnerabilities (GLSA 201808-04) — Gentoo security

https://security.gentoo.org/glsa/201808-04
generic🟡 PoC Available

GitHub - FSecureLABS/CVE-2018-4121: macOS 10.13.3 (17D47) Safari Wasm Exploit · GitHub

https://github.com/mwrlabs/CVE-2018-4121
generic
http://www.securitytracker.com/id/1040604

Vendor Advisories for CVE-2018-4121(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
redhatzenity-0:3.28.1-1.el72018-10-30redhat

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

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
webkit2gtk—
  • every version up to 2.20.0-2: fixed in 2.20.0-2
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
webkit2gtk—
  • every version up to 2.20.0-2: fixed in 2.20.0-2
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
webkit2gtk—
  • every version up to 2.20.0-2: fixed in 2.20.0-2
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
webkit2gtk—
  • every version up to 2.20.0-2: fixed in 2.20.0-2
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 6× in last 7d / 25× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 149 total refreshes for this CVE.

  1. 2026-10-09 20:03 UTCEPSS rescore
  2. 2026-10-08 16:37 UTCEPSS rescore
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  12. 2026-09-29 07:45 UTCOSV refresh
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  1. 2026-09-09 14:23 UTCOSV refresh
  2. 2026-09-06 13:44 UTCEPSS rescore
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  27. 2026-08-07 00:04 UTCOSV refresh
  28. 2026-08-06 13:42 UTCEPSS rescore
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  40. 2026-07-23 01:36 UTCEG score recompute
  41. 2026-07-22 22:16 UTCEG score recompute
  42. 2026-07-22 14:05 UTCEPSS rescore
  43. 2026-07-21 15:22 UTCEPSS rescore
  44. 2026-07-21 15:18 UTCOSV refresh
  45. 2026-07-20 17:04 UTCEPSS rescore
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  51. 2026-07-16 16:59 UTCEPSS rescore
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  66. 2026-07-04 10:56 UTCOSV refresh
  67. 2026-07-04 06:28 UTCEPSS rescore
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  75. 2026-06-28 04:53 UTCEPSS rescore

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 GitHub PoC) (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-44427✓ verified
    First seen Apr 9, 2018

    WebKit - WebAssembly Parsing Does not Correctly Check Section Order

    Open source ↗
  • GitHub PoCFSecureLABS/CVE-2018-4121
    First seen Apr 19, 2018

    macOS 10.13.3 (17D47) Safari Wasm Exploit

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2018-4121?
CVE-2018-4121 is a high vulnerability published on April 3, 2018. An issue was discovered in certain Apple products. iOS before 11.3 is affected. Safari before 11.1 is affected. iCloud before 7.4 on Windows is affected. iTunes before 12.7.4 on Windows is affected. tvOS before 11.3 is affected. watchOS before 4.3 is affected. The issue involves the "WebKit"…
When was CVE-2018-4121 disclosed?
CVE-2018-4121 was first published on April 3, 2018, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-4121 actively exploited?
CVE-2018-4121 is not currently on CISA's Known Exploited Vulnerabilities catalog. EchelonGraph's EG-KEV model classifies it as weaponized: a functional public exploit exists. FIRST EPSS estimates a 13% probability of exploitation in the next 30 days (96th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2018-4121?
CVE-2018-4121 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2018-4121?
A fix for CVE-2018-4121 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2018-4121 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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