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CVE Record

CVE-2026-20638: A logic issue was addressed with improved checks.

A logic issue was addressed with improved checks. This issue is fixed in iOS 26.3 and iPadOS 26.3. A user with Live Caller ID app extensions turned off could have identifying information leaked to the extensions.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2026-20638 is an Apple iOS/iPadOS privacy issue. Even when a user turned off Live Caller ID app extensions, identifying information could still be leaked to those extensions. Apple says the issue is fixed in iOS 26.3 and iPadOS 26.3.

Executive priority

Treat as a privacy remediation item with moderate urgency. It is not described as actively exploited, but it can expose identifying information despite a user privacy setting being disabled.

Technical view

Apple describes this as a logic issue addressed with improved checks. The CVSS vector is local, low complexity, no privileges required, user interaction required, with high confidentiality impact and no integrity or availability impact. The assigned weakness is CWE-284, improper access control.

Likely exposure

Exposure is limited to iPhone and iPad environments using affected iOS/iPadOS versions before 26.3, specifically where Live Caller ID app extensions are present and disabled by the user.

Exploitation context

The provided sources do not report active exploitation, and the CVE is not listed as KEV. Exploitation requires local context and user interaction per CVSS, and the impact is confidentiality-focused.

Researcher notes

Public detail is limited. Apple identifies a logic flaw fixed with improved checks, but does not provide extension behavior specifics or affected version ranges beyond the fixed releases. Avoid assuming broader impact without Apple confirmation.

Mitigation direction

  • Update eligible devices to iOS 26.3 or iPadOS 26.3.
  • Prioritize devices using Live Caller ID app extensions.
  • Check Apple’s advisory for any device-specific applicability details.
  • If immediate updating is delayed, review use of Live Caller ID extensions.

Validation and detection

  • Confirm device OS versions are iOS 26.3, iPadOS 26.3, or later.
  • Inventory devices with Live Caller ID app extensions installed.
  • Verify mobile device management compliance reports after updates.
  • Review Apple advisory 126346 for updated vendor guidance.
Prepared
Confidence
high
Sources
3

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 · medium confidence lookup

CWE-284: Authorization and privilege behavior lookup

Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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.

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cve · low confidence lookup

CVE-2026-20638 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
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

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

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.

1CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS vector scores

1 official score

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
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N1.83.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2026-20638Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
AppleiOS and iPadOS0Listed
Weakness

CWE details

CWE-284

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

CWE-284 · source CWE mapping

Improper Access Control

Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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