CVE-2026-20643

MEDIUMPre-NVD 5.45.4—
EchelonGraph scoreMEDIUM confidence

Score 5.4 from GitHub Security Advisory published 2026-03-18. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, ghsa
Trending — 4 sources updated this weekElevated
5.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.4Exploit: Elevated riskExposed: 0

A fix is available — apply it.

A cross-origin issue in the Navigation API was addressed with improved input validation. This issue is fixed in Background Security Improvements for iOS, iPadOS, and macOS, Safari 26.4, iOS 18.7.7 and iPadOS 18.7.7, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4. Processing maliciously crafted web content may bypass Same Origin Policy.

CVSS v3
5.4
EG Score
5.4(medium)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

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
Severity54% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
28%
KEV
Not listed

Published

March 17, 2026

Last Modified

June 17, 2026

References (7)

Vendor Advisories for CVE-2026-20643(11)

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

Patch Availability(11)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatwebkitgtk4-0:2.52.3-1.el7_92026-06-01redhat
redhatwebkit2gtk3-0:2.52.3-1.el9_02026-05-20redhat
redhatwebkit2gtk3-0:2.52.3-1.el9_82026-05-19redhat
redhatwebkit2gtk3-0:2.52.3-1.el9_22026-05-13redhat
redhatwebkit2gtk3-0:2.52.3-1.el8_42026-05-11redhat
redhatwebkit2gtk3-0:2.52.3-1.el9_42026-05-07redhat
redhatwebkit2gtk3-0:2.52.3-1.el8_62026-05-05redhat
redhatwebkit2gtk3-0:2.52.3-1.el8_82026-04-29redhat
redhatwebkit2gtk3-0:2.52.3-1.el9_62026-04-28redhat
redhatwebkit2gtk3-0:2.52.3-1.el8_102026-04-27redhat
redhatwebkit2gtk3-0:2.52.3-0.el9_7.12026-04-22redhat

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.

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 4× in last 7d / 4× 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.

  1. 2026-07-27 14:13 UTCEPSS rescore
  2. 2026-07-27 12:52 UTCEG score recompute
  3. 2026-07-27 12:52 UTCVendor advisory
  4. 2026-07-27 12:52 UTCGHSA enrichment

Publicly available exploits

(1 reference)

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

  • GitHub PoCzeroxjf/WebKit-NavigationAPI-SOP-Bypass
    First seen Mar 17, 2026

    WebKit NavigateEvent.canIntercept SOP bypass via cross-port interception — iOS 26.3.1 BSI (CVE-2026-20643)

    Open source ↗

Frequently asked(5)

What is CVE-2026-20643?
CVE-2026-20643 is a medium vulnerability published on March 17, 2026. A cross-origin issue in the Navigation API was addressed with improved input validation. This issue is fixed in Background Security Improvements for iOS, iPadOS, and macOS, Safari 26.4, iOS 18.7.7 and iPadOS 18.7.7, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4. Processing maliciously…
When was CVE-2026-20643 disclosed?
CVE-2026-20643 was first published in the National Vulnerability Database on March 17, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-20643 actively exploited?
CVE-2026-20643 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 72.0% of all scored CVEs.
What is the CVSS score of CVE-2026-20643?
CVE-2026-20643 has a CVSS v3.1 base score of 5.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-20643?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20643, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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