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Mallory
High

Gatekeeper quarantine bypass via crafted disk image in Apple Kernel

IdentifiersCVE-2026-28954CWE-693

CVE-2026-28954 is an Apple vulnerability described as a file quarantine bypass affecting iOS 18.7.9, iPadOS 18.7.9, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, and macOS Tahoe 26.5. Apple states that a maliciously crafted disk image may bypass Gatekeeper checks. The issue was addressed with additional checks. Based on the advisory language, the flaw allows attacker-controlled disk image content to evade the quarantine/Gatekeeper enforcement path that would normally validate untrusted downloaded content before execution or opening.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can bypass Gatekeeper protections for content delivered in a crafted disk image, reducing or eliminating a key macOS trust and quarantine control intended to warn or block users before opening untrusted software. This can enable subsequent delivery and execution of malicious payloads that would otherwise be subject to Gatekeeper scrutiny.

Mitigation

If you can’t patch tonight, do this now.

Until patched, minimize exposure to untrusted disk images and software obtained from untrusted or unsolicited sources. Restrict user ability to mount/open downloaded disk images where feasible, enforce application allowlisting or MDM controls, and verify downloaded software through trusted distribution channels rather than relying solely on Gatekeeper prompts. User caution is required because the exploit path involves a maliciously crafted disk image.

Remediation

Patch, then assume compromise.

Apply the vendor fixes provided by Apple: iOS 18.7.9, iPadOS 18.7.9, macOS Sequoia 15.7.7, macOS Sonoma 14.8.7, and macOS Tahoe 26.5. Apple indicates the issue was fixed by adding additional checks to prevent the quarantine bypass condition.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
AppleIpadosoperating_system
AppleIphone Osoperating_system
AppleMacosoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.