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CVE Record

CVE-2026-20658: A package validation issue was addressed by blocking the vulnerable package.

A package validation issue was addressed by blocking the vulnerable package. This issue is fixed in macOS Tahoe 26.3. An app may be able to gain root privileges.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-20658 is a macOS privilege escalation flaw. Apple says an app may be able to gain root privileges. That means a malicious or compromised local app could take full control of a Mac. Apple fixed the issue in macOS Tahoe 26.3 by blocking the vulnerable package.

Executive priority

Treat as a high-priority endpoint patching item. The business risk is full device takeover after local app execution, which can affect sensitive data, credentials, and endpoint availability. No public active exploitation is cited, but the impact justifies prompt update enforcement.

Technical view

Apple describes this as a package validation issue in macOS, fixed by blocking the vulnerable package. CVSS is 7.8 high: local attack vector, low complexity, low privileges required, no user interaction, and high confidentiality, integrity, and availability impact. No CWE is listed in the provided sources.

Likely exposure

Likely exposure is macOS systems not yet updated to macOS Tahoe 26.3 where users or processes can run local apps. The provided sources do not define exact vulnerable version ranges beyond Apple’s fixed release statement.

Exploitation context

This is a local privilege escalation issue. An attacker would need some ability to run an app on the target Mac, then could potentially gain root privileges. The source bundle does not indicate CISA KEV listing or active exploitation.

Researcher notes

Evidence is limited to Apple and CVE records. The affected range is not fully detailed in the bundle. The key technical clue is package validation failure, remediated by blocking a vulnerable package. Avoid assuming exploitability beyond the CVSS local, low-privilege model.

Mitigation direction

  • Update applicable macOS systems to macOS Tahoe 26.3 or later.
  • Review Apple advisory HT126348 for product-specific guidance.
  • Prioritize managed Macs that permit local app installation or execution.
  • Use MDM or endpoint management to enforce update compliance.
  • Limit untrusted app execution until affected systems are updated.

Validation and detection

  • Inventory macOS assets and identify Tahoe systems below 26.3.
  • Confirm installed macOS version through MDM or endpoint inventory.
  • Verify Apple security update compliance against HT126348.
  • Check update deployment success and investigate failed installations.
  • Monitor Apple guidance for any revised affected-version details.
Prepared
Confidence
medium
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

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CVE-2026-20658 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
7.8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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.

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
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-20658Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
ApplemacOS0Listed
Weakness

CWE details

No CWE listed

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