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CVE Record

CVE-2026-20664: The issue was addressed with improved memory handling.

The issue was addressed with improved memory handling. This issue is fixed in Safari 26.4, iOS 26.4 and iPadOS 26.4, macOS Tahoe 26.4, visionOS 26.4. Processing maliciously crafted web content may lead to an unexpected process crash.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-20664 is an Apple memory-handling flaw triggered by malicious web content. Apple says it can cause an unexpected process crash and fixed it in Safari 26.4, iOS/iPadOS 26.4, macOS Tahoe 26.4, and visionOS 26.4. The CVSS score is high, so treat unpatched endpoints as business-relevant exposure.

Executive priority

Prioritize patching in the normal emergency-to-high window for browsers and user endpoints. The vulnerability is remotely reachable through web content, but current provided evidence supports crash impact and high CVSS risk, not confirmed active exploitation.

Technical view

The bundle maps this to CWE-120 and CWE-787, consistent with memory corruption such as buffer overflow or out-of-bounds write. The vector is network-reachable with low complexity, no privileges, and required user interaction. Apple’s public wording only confirms process crash from crafted web content; it does not confirm code execution.

Likely exposure

Exposure is most likely on Apple endpoints using affected Safari, iOS/iPadOS, macOS Tahoe, or visionOS builds before 26.4. The Red Hat references indicate downstream tracking or advisories, but the provided bundle does not give enough product detail to define Red Hat exposure precisely.

Exploitation context

The bundle does not show CISA KEV listing, and no cited source states active exploitation. Practical exploitation would require a user or device to process maliciously crafted web content. Do not assume exploitation in the wild from this evidence alone.

Researcher notes

Key evidence is limited: Apple describes improved memory handling and unexpected process crash, while CVSS claims high confidentiality, integrity, and availability impact. Avoid overstating exploitability. Validate exact affected build ranges from Apple and downstream vendor advisories before broad risk scoring.

Mitigation direction

  • Update Safari to 26.4 or later where applicable.
  • Update iOS and iPadOS devices to 26.4 or later.
  • Update macOS Tahoe systems to 26.4 or later.
  • Update visionOS devices to 26.4 or later.
  • Review Red Hat advisories for environment-specific package guidance.
  • Prioritize managed browsers and high-risk user groups first.

Validation and detection

  • Inventory Apple devices and confirm installed OS or Safari versions.
  • Check vulnerability management data for CVE-2026-20664 detections.
  • Confirm update deployment success through MDM or endpoint telemetry.
  • Review Red Hat advisory applicability for any Linux packages in scope.
  • Monitor vendor pages for revised impact or exploitation guidance.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-120: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cwe · low confidence lookup

CWE-787: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-20664 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
8.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
19Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8.8CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9redhat-SADP
4.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L2.81.4CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2026-20664Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. ADP timelineredhat-SADP

    Made public.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
cvssV3_1other:ssvc
redhat-SADPwebkitgtk: Processing maliciously crafted web content may lead to an unexpected process crash
other:Red Hat severity ratingcvssV3_1
  • 2026-03-30T12:29:28.691Z: Reported to Red Hat.
  • 2026-03-28T20:00:00.000Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AppleSafari0Listed
AppleiOS and iPadOS0Listed
ApplemacOS0Listed
ApplevisionOS0Listed
Weakness

CWE details

CWE-120CWE-787

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-120 · source CWE mapping

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
CWE-787 · source CWE mapping

Out-of-bounds Write

Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs