CVE-2026-64705

Executive Summary

CVE-2026-64705 is a buffer overflow vulnerability affecting Apple macOS Sequoia and macOS Sonoma that was addressed with improved bounds checking. The flaw allows a locally running application to trigger unexpected system termination or write to kernel memory, indicating a privilege escalation and/or system stability compromise vector. Patch data is currently claimed by a single source (NVD) with no independent confirmation, and no public exploits or PoC code have been released as of this report.

Technical Analysis

The NVD description for CVE-2026-64705 identifies a buffer overflow condition that was remediated via improved bounds checking in the macOS operating system. The vulnerability is classified under CWE-120 (Buffer Copy without Checking Size of Input, commonly referred to as classic buffer overflow). While the description does not specify the affected system component, the stated impact — "write kernel memory" — strongly suggests the vulnerability exists in a kernel-adjacent subsystem or a system service that executes with elevated privileges.

Buffer overflows of this class occur when a program copies data into a fixed-size buffer without verifying that the source data fits within the allocated destination space. When the incoming data exceeds the buffer capacity, adjacent memory regions are overwritten. In the context of this vulnerability, an untrusted application can exploit this condition to overwrite kernel memory, which implies the vulnerable code path is exposed to user-mode processes through a kernel API, driver interface, or system service that lacks sufficient input validation.

The specific vulnerable component is not disclosed in the NVD description. The lack of CVE-assigned CWE data and the absence of a CVSS vector further limits the technical depth available for analysis. Based on the patch locations (macOS Sequoia 15.7.7 and macOS Sonoma 14.8.7), the vulnerability has existed across at least two major macOS releases, indicating a code path that has been present for a significant period.

The "improved bounds checking" patch language is a standard vendor phrasing for buffer overflow remediation and indicates the fix likely adds length validation routines before copy operations in the affected code path. The exact function names, call chains, and memory layout details are not publicly disclosed in the provided data; without a vendor advisory naming the affected component, these implementation specifics remain unavailable.

Exploitation Scenarios

Severity of information available: The NVD description provides no specific technical implementation details (no function names, no code paths, no syscall identifiers). The attack chain below is inferred from the buffer overflow vulnerability class and the stated impact — "app may be able to cause unexpected system termination or write kernel memory."

Insufficient technical detail available to construct a precise per-version exploitation path.

Attack Chain (Inferred from Vulnerability Class)

Step 1 — Reconnaissance / Target Identification The attacker must first have local execution capability on the target macOS system. This can be achieved through social engineering (e.g., a malicious document with macros), drive-by download, or bundling with legitimate software. Once the attacker can execute arbitrary code at the application layer, they begin enumerating the local system for vulnerable services and kernel interfaces. Without public disclosure of the specific vulnerable component, the attacker would need to fuzz kernel extension interfaces or system service input paths to identify the exact buffer overflow trigger.

Step 2 — Triggering the Flaw At the vulnerability-class level, the attacker crafts a payload that exceeds the expected buffer size in the vulnerable code path. The mechanism is to pass an oversized input to a system call, IOCTL, or IPC message handler that copies data into a fixed-size kernel buffer without proper length validation. The overrun overwrites adjacent kernel memory, potentially including return addresses, function pointers, or other structured data.

Step 3 — Payload Execution Method Because the overflow enables writes to kernel memory, the attacker can position shellcode or ROP (Return-Oriented Programming) chains within kernel address space. For a denial-of-service scenario, the attacker may simply corrupt kernel structures to trigger a panic (unexpected system termination). For privilege escalation, the attacker would craft the overflow to overwrite a kernel function pointer or security context structure, enabling code execution with kernel privileges — result in gaining root or kernel-level capabilities from an unprivileged application context.

Step 4 — Post-Exploitation Impact Once kernel memory can be written, the attacker gains the ability to:

• Bypass macOS security mechanisms (SIP — System Integrity Protection, TCC — Transparency, Consent, and Control, code signing enforcement).
• Install persistent kernel-level implants or rootkits that survive reboots.
• Read and modify arbitrary process memory, exfiltrating credentials, encryption keys, and sensitive data.
• Escalate from a standard user context to either root or kernel execution.
• Cause repeated system crashes as a denial-of-service mechanism against critical infrastructure running macOS.

Note on PoC status: No public PoC exists, and no exploit code has been observed in the wild. This attack chain represents the theoretical exploitation vector for the stated vulnerability class. The absence of known exploitation in the wild is consistent with the claimed — but unconfirmed — patch status.

Impact Assessment

CVSS Assessment: As of this report, no CVSS vector or score has been assigned by the CNA/NVD. The lack of a CVSS score limits quantitative risk scoring; the impact is therefore assessed qualitatively.

Business Impact:

• Confidentiality: High — kernel memory writes can expose sensitive data held in kernel buffers (cryptographic keys, credential material, process memory).
• Integrity: High — the ability to write kernel memory allows an attacker to manipulate security policies, patch runtime kernel code, and subvert file integrity checks.
• Availability: High — the description explicitly notes "unexpected system termination," meaning a local attacker can crash the system at will. Sophisticated exploitation could yield kernel-level code execution allowing arbitrary system commands.

Affected Systems: All macOS systems running:

• macOS Sequoia prior to version 15.7.7
• macOS Sonoma prior to version 14.8.7

This places a substantial portion of the enterprise macOS fleet at risk, as both major versions span the most recent two-year release cycle of Apple's operating system. Systems with managed update policies that have not yet deployed the 15.7.7 or 14.8.7 security updates remain unpatched.

Blast Radius:

• Local attacker with application-level execution privileges can either:
  1. Crash the system (denial of service)
  2. Write arbitrary kernel memory (privilege escalation to kernel context)
• Enterprise implications: The vulnerability effectively removes the security boundary between the user application layer and the kernel. A compromised user-space application (e.g., through a browser exploit chain) becomes a kernel-level compromise. For organizations managing fleets of macOS endpoints, this CVE represents a single-locus failure point for full system compromise.

Exploitability Factors:

• Requires local code execution: moderate barrier (lowers severity versus a remote attack).
• Kernel address space layout randomization (KASLR) on modern macOS complicates exploitation but is not an absolute prevention.
• No known in-the-wild exploitation as of this report.

Detection Guidance

The following detection rules target the observable behavior of buffer overflow exploitation attempts on macOS, including abnormal kernel panic logs, excessive memory copy operations, crash reports, and unusual system call patterns. These rules are generalized since the exact I/O patterns of CVE-2026-64705 are not publicly disclosed.

Sigma Rule

title: macOS Kernel Buffer Overflow Exploitation Attempt
id: 5f7c1a2a-9d3b-4e8e-a6b4-39c8d81e6f22
status: experimental
description: Detects abnormal kernel panic or crash report generation following local application execution, potentially indicating buffer overflow exploitation against macOS kernel subsystems (CVE-2026-64705).
logsource:
    product: macOS
    category: process_creation
detection:
    selection_panic:
        EventID:
            - 'panic'
            - 'kern.crash'
        CommandLine|contains:
            - 'kernel panic'
            - 'memory corruption'
            - 'buffer overflow'
    selection_crash_reporter:
        Image|endswith: '/ReportCrash'
        CommandLine|contains:
            - 'Kernel'
            - 'kernelmanagerd'
    condition: selection_panic or selection_crash_reporter
falsepositives:
    - Legitimate kernel panics caused by hardware issues
    - Third-party kernel extension bugs
level: high
tags:
    - attack.t1203
    - cve.2026-64705

YARA Rule

rule CVE_2026_64705_macOS_BufferOverflow
{
    meta:
        author = "ValterSIT Threat Intel"
        description = "Detects crash reports or strings associated with kernel buffer overflow on macOS"
        cve = "CVE-2026-64705"
        date = "2026-01-01"
        reference = "NVD CVE-2026-64705"
    strings:
        $panic1 = "kernel panic" ascii nocase
        $panic2 = "Buffer overflow" ascii nocase
        $panic3 = "corrupted" ascii nocase
        $panic4 = "unexpected system termination" ascii nocase
        $panic5 = "macOS Sequoia 15.7.7" ascii nocase
        $panic6 = "macOS Sonoma 14.8.7" ascii nocase
        $p = {48 8B 05 ?? ?? ?? ?? 48 89 45 F8 48 8B 45 F8} // typical x86_64 prologue
    condition:
        (any of ($panic*) and filesize < 10MB)
        or ($p and any of ($panic*))
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2026-64705 Potential macOS Kernel Overflow - Suspicious IPC/Updater Traffic"; flow:to_server; content:"|ff ff ff ff|"; offset:0; depth:4; content:"com.apple"; nocase; within:256; content:"update"; nocase; within:512; sid:202664705; rev:1; metadata:cve CVE-2026-64705; classtype:attempted-admin;)

Elastic Detection

// Elastic EQL rule to detect macOS crash reports and kernel panic events
sequence by host.name with maxspan=5m
  [ process where event.type == "start" and
      process.name : "ReportCrash" and
      process.args : ("*Kernel*", "*kernelmanagerd*")
  ]
  [ file where event.action in ("modification", "create") and
      file.path : "/Library/Logs/DiagnosticReports/*.panic"
  ]

Splunk SPL Query

index=macos sourcetype="ossec" OR sourcetype="macos:system" 
| search "panic" OR "kernel" OR "memory" OR "buffer" 
| where match(message, "(?i)(kernel panic|buffer overflow|memory corruption)")
| eval cve="CVE-2026-64705"
| table _time, host, source, message, cve
| stats count by host, cve

Wazuh OSSEC Rule

<group name="macos_kernel_overflow,">
  <rule id="100717" level="12">
    <if_sid>100001</if_sid>
    <match>kernel panic</match>
    <match>buffer overflow</match>
    <match>memory corruption</match>
    <description>CVE-2026-64705: Possible kernel buffer overflow on macOS host</description>
    <group>cve,2026-64705,kernel_overflow,</group>
    <alert_level>12</alert_level>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 2/4 — CLAIMED. The patch is claimed by a single source (NVD) and not independently confirmed by Apple's official security advisory as of this report.

Immediate Mitigations (Before Patch Deployment)

1. Restrict local execution surfaces: Limit application installation to trusted developers only. Enforce signed-app-only policy in managed environments via MDM (Mobile Device Management).
2. Follow least-privilege principles: Run applications with least-privilege user accounts — not as administrator — to reduce the probability of reaching the vulnerable kernel code path.
3. Deploy Gatekeeper/Firewall hardening: Use macOS Gatekeeper and application quarantine to prevent untrusted apps from launching.
4. Enable crash report monitoring: Collect kernel panic and crash report logs centrally (e.g., via SIEM) to detect attempted exploitation if present in the environment.
5. No workaround is provided by the vendor or NVD; the only remediation path is the update itself.

Patch/Upgrade Steps

1. Validate the claim: Verify that Apple has published a formal security advisory matching the NVD entry. Monitor Apple security updates page and retract the update if advisories do not confirm the fix.
2. Deploy via MDM: Distribute macOS Sequoia 15.7.7 and macOS Sonoma 14.8.7 — or later — to all eligible fleets. Use a phased rollout (pilot -> production) to minimize operational risk.
3. Update Catalina/Big Sur/Monterey/Ventura systems: While the description lists only Sequoia and Sonoma, presume all older supported macOS versions are equally affected and plan upgrade paths accordingly.
4. Test critical LOB applications against the updated build before general deployment, as OS upgrades can break legacy applications.

Long-Term Hardening

1. Establish a 30-day patch SLA for macOS endpoints to reduce exposure windows for future kernel-level CVEs of this class.
2. Leverage Endpoint Detection and Response (EDR) on macOS endpoints with kernel-level telemetry (e.g., Sysmon for macOS equivalent) to monitor system call and kernel interface interactions.
3. Review and reduce the number of kernel extensions loaded on organization macOS devices; each third-party kext increases the attack surface for kernel-level memory corruption bugs.
4. Train users on safe application handling to prevent initial local code execution vectors (phishing, malware bundling) prior to the patch being deployed.

References

1. NVD Entry — CVE-2026-64705: https://nvd.nist.gov/vuln/detail/CVE-2026-64705
2. Apple macOS Sequoia 15.7.7 Security Notes (when published): https://support.apple.com/en-us/HT201222
3. Apple macOS Sonoma 14.8.7 Security Notes (when published): https://support.apple.com/en-us/HT201222
4. MITRE CWE-120 — Buffer Copy without Checking Size of Input: https://cwe.mitre.org/data/definitions/120.html
5. FIRST EPSS — CVE-2026-64705 (not yet scored): https://www.first.org/epss/

Campaign Notes: No known threat actor campaigns have been reported in connection with CVE-2026-64705. No exploit-in-the-wild evidence exists. CISA KEV: Not listed. PoC: None public. The "claimed" patch confidence indicates that while NVD lists the version fix, an official Apple advisory confirming the fix has not yet been independently published or cross-referenced.