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CVE Record

CVE-2026-28859: 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, tvOS 26.4, visionOS 26.4, watchOS 26.4. A malicious website may be able to process restricted web content outside the sandbox.

HighCVSS 8.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This Apple vulnerability could let a malicious website escape normal web-content restrictions on affected Apple platforms. Apple says it was fixed with improved memory handling in version 26.4 releases. Because compromise can follow normal web browsing and the CVSS score is 8.8, organizations should treat it as high priority for Apple endpoint patching.

Executive priority

Prioritize remediation in the next normal emergency patch window for managed Apple endpoints, especially systems used for web browsing. There is no active exploitation evidence in the bundle, but the high impact and low attack complexity justify rapid patch verification.

Technical view

CVE-2026-28859 is a memory-handling flaw affecting Safari and multiple Apple operating systems. The published impact is that a malicious website may process restricted web content outside the sandbox. The CVSS vector indicates network attack surface, low complexity, no privileges, required user interaction, and high confidentiality, integrity, and availability impact.

Likely exposure

Exposure is most likely on Apple devices or Safari installations below the fixed 26.4 versions listed by Apple. The bundle names Safari, iOS and iPadOS, macOS Tahoe, tvOS, visionOS, and watchOS, but does not provide detailed vulnerable build ranges.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. The stated scenario involves a malicious website and requires user interaction. No public exploit mechanics are included in the provided sources.

Researcher notes

Apple’s description is brief and does not identify a specific WebKit component, crash condition, or root-cause class beyond improved memory handling and broad CWE mappings. Treat the listed CWE set as taxonomy, not proof of a single bug type. Avoid assuming exploitability beyond the published malicious-website scenario.

Mitigation direction

  • Update Safari to 26.4 where applicable.
  • Update iOS and iPadOS devices to 26.4.
  • Update macOS Tahoe systems to 26.4.
  • Update tvOS, visionOS, and watchOS to 26.4 where deployed.
  • Review Apple and relevant vendor advisories for environment-specific guidance.

Validation and detection

  • Inventory Apple devices and Safari versions across managed assets.
  • Confirm installed versions match Apple’s fixed 26.4 releases.
  • Check MDM compliance reports for pending Apple updates.
  • Review browser-related security alerts after suspected malicious-site exposure.
  • Track Red Hat advisories only where referenced products are present.
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-125: 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-416: 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-2026-28859 mapping review

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

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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
21Source 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:L/I:N/A:N2.81.4CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2026-28859Attack 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: A malicious website may be able to process restricted web content outside the sandbox
other:Red Hat severity ratingcvssV3_1
  • 2026-03-30T12:36:23.943Z: 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
AppletvOS0Listed
ApplevisionOS0Listed
ApplewatchOS0Listed
Weakness

CWE details

CWE-120CWE-125CWE-416CWE-787

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