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CVE Record

CVE-2026-20636: The issue was addressed with improved memory handling.

The issue was addressed with improved memory handling. This issue is fixed in Safari 26.3, iOS 26.3 and iPadOS 26.3, macOS Tahoe 26.3, visionOS 26.3. 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

Apple reports a memory-handling flaw where malicious web content can crash an affected process. The fixed products listed are Safari 26.3, iOS 26.3 and iPadOS 26.3, macOS Tahoe 26.3, and visionOS 26.3. Treat this as urgent for managed Apple endpoints that browse the web.

Executive priority

Prioritize within the normal emergency browser and endpoint patch cycle. The CVSS score is high and the attack path is web content, but current supplied evidence does not establish active exploitation.

Technical view

CVE-2026-20636 is a memory-safety issue mapped to CWE-119 and CWE-120. The CVSS 3.1 vector is 8.8 high, network reachable, low complexity, no privileges, and user interaction required. Apple’s description states crafted web content may cause an unexpected process crash; the bundle does not provide deeper root-cause detail.

Likely exposure

Exposure is most likely on Apple devices or Safari installations below the fixed versions listed in Apple advisories. The supplied affected version data is incomplete, so confirm exact vulnerable ranges from Apple guidance and device inventory.

Exploitation context

The source bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires a user to process maliciously crafted web content. No exploit code, public exploit maturity, or attack campaign detail is provided.

Researcher notes

The main uncertainty is impact detail. Apple’s summary mentions process crash, while the CVSS vector marks high confidentiality, integrity, and availability impact. Validate against Apple’s advisory text and any downstream vendor records before expanding impact claims.

Mitigation direction

  • Update Safari to 26.3 or later where applicable.
  • Update iOS and iPadOS devices to 26.3 or later.
  • Update macOS Tahoe systems to 26.3 or later.
  • Update visionOS devices to 26.3 or later.
  • Check Apple advisories for exact platform-specific guidance.
  • Review Red Hat advisories only for Red Hat-managed package relevance.

Validation and detection

  • Inventory Safari, iOS, iPadOS, macOS Tahoe, and visionOS versions.
  • Confirm managed devices report the fixed 26.3 releases or later.
  • Check vulnerability scanner detections against CVE-2026-20636.
  • Review Apple security update records for successful installation.
  • Monitor KEV and vendor pages for exploitation-status changes.
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-119: 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-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
cve · low confidence lookup

CVE-2026-20636 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
6.5CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H2.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

8.8High
CVSS 3.1 vector shape for CVE-2026-20636Attack 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
  • 2026-03-18T20:19:05.331Z: Reported to Red Hat.
  • 2026-03-18T00:00:00.000Z: 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-119CWE-120

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

CWE-119 · source CWE mapping

Improper Restriction of Operations within the Bounds of a Memory Buffer

Improper Restriction of Operations within the Bounds of a Memory Buffer represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

Open CWE intelligenceSame-CWE CVEs
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