Out-of-bounds write in Apple mDNSResponder
CVE-2026-43666 is an out-of-bounds write vulnerability in Apple's mDNSResponder component. Apple states the issue was addressed with improved bounds checking. The flaw is reachable by an attacker on the local network and affects multiple Apple platforms, including iOS/iPadOS, macOS, tvOS, visionOS, and watchOS. The available content does not identify the specific vulnerable function or code path beyond mDNSResponder.
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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.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
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.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
21 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A local network denial-of-service vulnerability affecting mDNSResponder.
An out-of-bounds write vulnerability in macOS Tahoe that may allow an attacker on the local network to cause a denial-of-service.
An out-of-bounds write vulnerability in Apple TV software that could allow a local-network attacker to cause denial of service.
An out-of-bounds write vulnerability in macOS Sonoma that may allow a local network attacker to cause a denial of service.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.