CVE-2026-43692

Executive Summary

CVE-2026-43692 is an input-validation weakness (CWE-20) in Apple macOS that was addressed through improved input sanitization. A remote attacker can trigger the flaw against a macOS host and, per the vendor description, cause an "unexpected app termination or arbitrary code execution." The vulnerability carries a CVSS 3.1 base score of 8.8 (High) with a network attack vector, low attack complexity, no privileges required, and user interaction required (AV:N/AC:L/PR:N/UI:R). Patches are available in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7, but the fix is only CLAIMED by a single source and is not independently confirmed.

Technical Analysis

CVE-2026-43692 is classified under CWE-20 (Improper Input Validation). The NVD description is deliberately terse and states only that "a validation issue was addressed with improved input sanitization" and that the fix ships in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7. From this we can derive the following defensible facts:

• Vulnerability class: Improper input validation (CWE-20) — the software fails to correctly validate or sanitize externally supplied input before it is used in a security-relevant operation.
• Root cause category: The vendor's remediation language ("improved input sanitization") indicates the original defect was in how input was parsed, filtered, or normalized before consumption by an internal component.
• Attack surface: Given AV:N (network) and UI:R (user interaction) in the CVSS vector, the flaw is reachable over the network but requires some form of user action to trigger. This is consistent with a client- or content-facing parsing path on macOS where a remote party delivers data (for example, a document, media, archive, or network-delivered payload) that the user must open or approve.
• Impact class: The description explicitly allows two outcomes — "unexpected app termination" (denial of service) or "arbitrary code execution" (full code execution in the context of the affected process). The CVSS subscores C:H/I:H/A:H confirm high confidentiality, integrity, and availability impact, meaning successful exploitation can fully compromise the target process.

Important caveat: The NVD description does NOT name any specific function, API, parser, library, file path, or protocol. No function/class names, endpoints, or parameters are provided. This report therefore describes the vulnerability class and mechanism in general terms and does not invent implementation specifics. Where the description is silent (for example, the exact component, the exact malformed input, the exact trigger), we explicitly note that insufficient technical detail is available.

The combination of AV:N, AC:L, PR:N, UI:R, and S:U indicates:

• The attacker does not need credentials (PR:N).
• The attack is not complex — no race condition or unusual preconditions (AC:L).
• The vulnerability affects the local security scope rather than propagating to adjacent components (S:U), i.e., exploitation impacts the vulnerable process and its resources, not an unrelated privilege domain directly.
• Some user action is required (UI:R), which is typical of client-side parsing bugs.

Because it is a CWE-20 issue on macOS, the practical security concern is that input delivered over the network can reach an unvalidated code path in a user context. If exploitation of the arbitrary-code-execution outcome occurs in a process that holds sensitive entitlements or user credentials, an attacker could gain code execution with the victim's user privileges, potentially escalating the blast radius depending on the compromised component.

Exploitation Scenarios

No public PoC, exploit code, or Nuclei template is available. CVE-2026-43692 is NOT in CISA KEV, and EPSS is 0.00514 (42.4th percentile), indicating low observed likelihood of exploitation at the time of writing. The attack chain below is inferred strictly from the vulnerability class (CWE-20 input-validation failure) and the CVSS vector (AV:N / AC:L / PR:N / UI:R); no specific implementation details are fabricated.

1. Reconnaissance / target identification An attacker identifies a macOS host running a version prior to the fixed releases (macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7). This could be done through normal network footprinting, phishing targeting, or knowledge of a user's environment. Because the attack vector is network (AV:N) and no privileges are required (PR:N), the attacker does not need prior access or credentials to the target.

2. Triggering the specific flaw class The flaw is an input-validation failure (CWE-20). In a client-facing input-validation vulnerability, the attacker delivers malformed, over-long, or otherwise unexpected input that reaches the component before proper sanitization. Because the vector requires user interaction (UI:R), the attacker must get the victim to open, load, or approve the delivered content. The exact input format and delivery channel are not specified in the NVD description and therefore are not asserted here — the operative point is that a remote party controls the input, and insufficient validation allows it to reach a security-sensitive code path.

3. Payload / execution method at the vulnerability-class level For an input-validation flaw of this type, exploitation typically means crafting input that bypasses the (missing or insufficient) sanitization so that the program processes attacker-influenced data as if it were trusted. Success is characterized in the vendor description as either an unexpected app termination or arbitrary code execution. No specific payload structure is documented publicly, so the concrete byte-level payload is not described.

4. Post-exploitation impact If the arbitrary-code-execution outcome is achieved, the attacker obtains code execution in the context of the affected process under the victim's user account. Depending on that process's permissions and entitlements, this may allow access to user data, manipulation of files, or further lateral movement within the user's session. The CVSS C:H/I:H/A:H ratings reflect full loss of confidentiality, integrity, and availability for the vulnerable component. If only the DoS outcome is achieved, the impact is a crash/termination of the affected application (availability impact).

Impact Assessment

• CVSS 3.1 base score: 8.8 (High) — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
• Attack Vector (AV:N): Exploitable over a network; the attacker does not need local access.
• Attack Complexity (AC:L): No special conditions; the flaw is straightforward to trigger once the input is delivered.
• Privileges Required (PR:N): The attacker needs no prior privileges or credentials.
• User Interaction (UI:R): The victim must perform an action (open/approve content) for exploitation.
• Scope (S:U): Impact is confined to the vulnerable component's security scope.
• Confidentiality/Integrity/Availability (C:H/I:H/A:H): High impact across all three — the worst outcome is arbitrary code execution with total loss of C/I/A for the affected process.

Blast radius: Any macOS host below the fixed versions is potentially affected. Because the impact can be arbitrary code execution, and because the EPSS is low but the score is high, the primary business risk is compromise of managed macOS endpoints (laptops and desktops). Sensitive consequences depend on the privileges and entitlements of the vulnerable component: data theft, tampering, or persistent footholds in the user session. Enterprise environments with many macOS endpoints and users who routinely open content from email or the web are the most exposed.

Exploitation status: No public exploit, no Nuclei template, no KEV listing. EPSS 0.00514 indicates low current exploitation probability, but the severity warrants prompt patching given the code-execution potential.

Detection Guidance

Sigma Rule

title: Possible Exploitation of CVE-2026-43692 (macOS Input Validation)
id: 5f4c1b9e-3a7d-4c2e-9b1a-7d6e2f0a8c11
status: experimental
description: Detects abnormal process termination and crash telemetry consistent with exploitation of a macOS input-validation vulnerability (CWE-20).
references:
  - https://nvd.nist.gov/vuln/detail/CVE-2026-43692
author: valtersit.com
date: 2026-01-01
logsource:
  product: macos
  category: process_creation
detection:
  selection_crash:
    EventType:
      - 'crash'
      - 'abnormal_termination'
  selection_ctx:
    ParentImage|endswith:
      - '/Safari'
      - '/Mail'
      - '/Preview'
      - '/QuickTime Player'
      - '/Finder'
  condition: selection_crash and selection_ctx
fields:
  - Image
  - ParentImage
  - CommandLine
  - User
falsepositives:
  - Legitimate application crashes unrelated to exploitation
level: medium
tags:
  - attack.t1203
  - cve.2026.43692

YARA Rule

rule CVE_2026_43692_macOS_InputValidation_Generic
{
    meta:
        author      = "valtersit.com"
        description = "Generic placeholder detection for potential exploit artifacts associated with CVE-2026-43692. No public indicator of compromise is available; this rule is intentionally broad and must be tuned."
        reference   = "https://nvd.nist.gov/vuln/detail/CVE-2026-43692"
        date        = "2026-01-01"
        cve         = "CVE-2026-43692"
        severity    = "high"
    strings:
        $macho = { CF FA ED FE }
        $cve   = "CVE-2026-43692" ascii nocase
        $tgt1  = "GoldenGate" ascii wide nocase
        $tgt2  = "Tahoe" ascii wide nocase
    condition:
        $macho at 0 and ($cve or $tgt1 or $tgt2)
}

Suricata IDS Rule

alert tcp any any -> $HOME_NET any (msg:"CVE-2026-43692 Possible macOS Input Validation Exploitation Attempt"; flow:to_client,established; threshold:type limit, track by_src, count 1, seconds 60; classtype:attempted-user; reference:cve,2026-43692; reference:url,nvd.nist.gov/vuln/detail/CVE-2026-43692; metadata:attack_target Client_Endpoint, created_at 2026_01_01, cve CVE_2026_43692, signature_severity Major; sid:2026436920; rev:1;)

Note: No specific protocol signature, URI, or payload byte pattern is published for this CVE. This rule is a placeholder for the vulnerable traffic class and requires environment-specific tuning (e.g., adding protocol/port and payload content once indicators are available).

Elastic Detection

sequence by host.id with maxspan=30s
  [process where event.type == "start" and process.parent.name in ("Safari", "Mail", "Preview", "QuickTime Player")] 
  [process where event.action == "end" and process.exit_code != 0]

Note: This EQL rule surfaces a user-facing application spawning a child process that then exits abnormally — a behavioral pattern consistent with a client-side input-validation crash. No CVE-specific field or signature is available, so this is a class-level detection requiring tuning.

Splunk SPL Query

index=endpoint sourcetype=macos:crash OR sourcetype=macos:unified_log
| search ("Golden Gate" OR "Sequoia" OR "Tahoe" OR "macOS")
| where (exit_code!=0 OR match(_raw, "(?i)crash|abnormal termination|signal"))
| stats count min(_time) as first_seen max(_time) as last_seen by host, process_name, parent_process
| where count > 0
| convert ctime(first_seen) ctime(last_seen)
| sort - count

Note: No CVE-specific signature is published. This query hunts for crash/abnormal-termination telemetry on macOS hosts and should be correlated with vulnerability scanning data (versions below the fixed releases).

Wazuh OSSEC Rule

<group name="macos,cve-2026-43692,">
  <rule id="100692" level="9">
    <decoded_as>json</decoded_as>
    <field name="event_type">crash|abnormal_termination</field>
    <description>CVE-2026-43692: macOS application crash/abnormal termination possibly related to input-validation exploitation</description>
    <mitre>
      <id>T1203</id>
    </mitre>
    <group>cve_2026_43692,macos,</group>
  </rule>
</group>

Note: This rule depends on macOS crash telemetry being ingested into Wazuh. No CVE-specific field is published, so the rule keys on the crash/abnormal-termination event class.

Mitigation & Patch Guidance

Patch confidence: 2/4 (CLAIMED — single source (NVD) claims a patch; not independently confirmed). Verify the fix by cross-referencing Apple's own security advisories before relying solely on this classification.

1. Immediate mitigations (until patched/verified):

   • Update macOS to one of the fixed releases: macOS Golden Gate 27, macOS Sequoia 15.8, or macOS Tahoe 26.7 or later.
   • Restrict user interaction with untrusted content: block or warn on risky email attachments and untrusted web content; reduce the attack surface by limiting which file/content types are auto-opened.
   • Use endpoint detection to alert on abnormal application terminations involving content-handling applications (Safari, Mail, Preview, QuickTime Player) so that potential exploitation attempts are visible even before patching.
   • Segment high-value macOS endpoints and enforce least privilege to limit the impact of arbitrary code execution in a user context.

2. Patch / upgrade steps:

   • Confirm the currently installed macOS build on all managed endpoints.
   • Apply the fixed update for the relevant track (Golden Gate 27, Sequoia 15.8, Tahoe 26.7) via your MDM/software-update pipeline.
   • Because the patch is only CLAIMED by a single source, validate remediation against Apple's published security advisory for the corresponding macOS release before closing the finding.

3. Long-term hardening:

   • Maintain an authoritative inventory of macOS versions across the fleet and enforce update SLAs to prevent drift into unsupported or vulnerable builds.
   • Apply application allowlisting and content-type restrictions to reduce exposure to client-side parsing and input-validation flaws.
   • Continuously monitor EPSS and CISA KEV for changes in exploitation status; if CVE-2026-43692 is added to KEV or public exploit code emerges, treat remediation as emergency change.
   • Log and retain macOS crash/unified-log telemetry centrally to support retrospective hunting for exploitation attempts.

References

• NVD — CVE-2026-43692: https://nvd.nist.gov/vuln/detail/CVE-2026-43692
• Apple Security Releases (vendor advisories for macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7): https://support.apple.com/en-us/HT201222
• CWE-20 — Improper Input Validation: https://cwe.mitre.org/data/definitions/20.html
• MITRE ATT&CK T1203 — Exploitation for Client Execution: https://attack.mitre.org/techniques/T1203/
• CISA Known Exploited Vulnerabilities Catalog (status check — CVE-2026-43692 NOT listed as of report date): https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Threat actor / exploitation note: No public PoC, exploit code, or Nuclei template exists for CVE-2026-43692, and it is not in CISA KEV. EPSS is 0.00514 (~42.4th percentile), indicating low likelihood of active exploitation at this time. No known threat actor campaigns are associated with this CVE in the available data. All exploitation details in this report are inferred from the vulnerability class (CWE-20) and the CVSS vector, not from observed in-the-wild activity.