A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.7.7 and iPadOS 18.7.7, iOS 26.3 and iPadOS 26.3, macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.3, tvOS 26.3, visionOS 26.3, watchOS 26.3. An app may be able to cause unexpected system termination.
CVE-2026-20637
MEDIUMPre-NVD 6.26.2—Trending — 3 sources updated this weekElevated
EchelonGraph scoreMEDIUM confidence
Score 6.2 from GitHub Security Advisory published 2026-03-25. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 6.2; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, ghsa
6.2EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.2Exploit: Elevated riskExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.2
- EG Score
- 6.2(medium)
- EG Risk
- 28(Track)EG Risk 28/100SSVC: 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 computedSeverity62% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 10%
- KEV
- Not listed
Published
March 25, 2026
Last Modified
June 17, 2026
References (8)
- product-security@applehttps://support.apple.com/en-us/126346
- product-security@applehttps://support.apple.com/en-us/126348
- product-security@applehttps://support.apple.com/en-us/126351
- product-security@applehttps://support.apple.com/en-us/126352
- product-security@applehttps://support.apple.com/en-us/126353
- product-security@applehttps://support.apple.com/en-us/126793
- product-security@applehttps://support.apple.com/en-us/126795
- product-security@applehttps://support.apple.com/en-us/126796
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 5× in last 7d / 5× 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.
- 2026-08-01 04:15 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-27 14:13 UTCEPSS rescore
- 2026-07-27 12:50 UTCEG score recompute
- 2026-07-27 12:50 UTCGHSA enrichment
Publicly available exploits
(2 references)Working exploit code is in the public domain (2 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- GitHub PoCzeroxjf/CVE-2026-20637-AppleSEPKeyStore-UAFFirst seen Jan 13, 2026
CVE-2026-20637: AppleSEPKeyStore Use-After-Free — iOS/macOS kernel vulnerability (patched in 26.4)
Open source ↗ - GitHub PoC0xjohnnydev/CVE-2026-20637-AppleSEPKeyStore-UAFFirst seen Jan 13, 2026
CVE-2026-20637: AppleSEPKeyStore Use-After-Free — iOS/macOS kernel vulnerability (patched in 26.4)
Open source ↗
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-20637?
CVE-2026-20637 is a medium vulnerability published on March 25, 2026. A use after free issue was addressed with improved memory management. This issue is fixed in iOS 18.7.7 and iPadOS 18.7.7, iOS 26.3 and iPadOS 26.3, macOS Sequoia 15.7.5, macOS Sonoma 14.8.5, macOS Tahoe 26.3, tvOS 26.3, visionOS 26.3, watchOS 26.3. An app may be able to cause unexpected system…
When was CVE-2026-20637 disclosed?
CVE-2026-20637 was first published in the National Vulnerability Database on March 25, 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-2026-20637 actively exploited?
CVE-2026-20637 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 90.2% of all scored CVEs.
What is the CVSS score of CVE-2026-20637?
CVE-2026-20637 has a CVSS v3.1 base score of 6.2 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-20637?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-20637, 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
Explore the affected products and dependency analysis for CVE-2026-20637
Is Your Infrastructure Affected by CVE-2026-20637?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.