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CVE Record

CVE-2026-20635: 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 18.7.5 and iPadOS 18.7.5, iOS 26.3 and iPadOS 26.3, macOS Tahoe 26.3, tvOS 26.3, visionOS 26.3, watchOS 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

This is a high-severity Apple web content memory handling flaw. A malicious webpage or web-delivered content could crash the affected process. Apple says the issue is fixed across Safari, iOS/iPadOS, macOS, tvOS, visionOS, and watchOS 26.3-era releases, plus iOS/iPadOS 18.7.5.

Executive priority

Prioritize normal emergency patch handling for managed Apple fleets, especially executive, developer, and externally exposed browsing environments. There is no provided evidence of active exploitation, but the web-content attack path and high CVSS justify rapid rollout.

Technical view

The CVE maps to CWE-119/CWE-120 memory handling errors. The CVSS 3.1 vector is 8.8, network-reachable, low complexity, no privileges required, but requiring user interaction. Public Apple text confirms a crash outcome; the CVSS vector indicates broader confidentiality, integrity, and availability impact, but details are limited.

Likely exposure

Exposure is most likely on Apple devices or Safari installations that process untrusted web content and have not been updated to the fixed versions named by Apple.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. Treat exploitation status as unconfirmed; risk comes from web-content attack surface, low complexity, and broad Apple platform reach.

Researcher notes

The public record is sparse: Apple names improved memory handling and process crash, while CVSS indicates high CIA impact. Affected version data in the bundle is not granular. Do not infer exploitability beyond malicious web content processing and user interaction.

Mitigation direction

  • Update Safari to 26.3 where applicable.
  • Update iOS and iPadOS to 18.7.5 or 26.3.
  • Update macOS Tahoe, tvOS, visionOS, and watchOS to 26.3.
  • Use Apple advisories to confirm exact supported device and build applicability.
  • Prioritize devices used for browsing untrusted links or high-risk communications.

Validation and detection

  • Inventory Apple endpoints and Safari versions against Apple fixed-release advisories.
  • Confirm managed devices report the fixed OS or Safari build.
  • Review browser crash telemetry for unusual web content process crashes.
  • Check vulnerability scanners for CVE-2026-20635 coverage and false positives.
  • Track Apple and Red Hat advisories for any clarified package impact.
Prepared
Confidence
medium
Sources
11

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-2026-20635 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
22Source 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-2026-20635Attack 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
  • 2026-03-18T20:18:01.074Z: 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 iPadOS0, 0Listed
ApplemacOS0Listed
AppletvOS0Listed
ApplevisionOS0Listed
ApplewatchOS0Listed
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