Kernel memory write via VFS mapping race
Published Dec 12, 2025 · Updated Dec 12, 2025
Kernel memory corruption in Apple iOS, iPadOS, macOS, tvOS, visionOS, and watchOS allows local users to write kernel memory or crash the system. XNU VFS contiguous I/O re-fetches a user mapping without confirming that it remains physically contiguous, so a mapping-swap race directs access to unrelated physical pages. A locally running malicious app must win the race; successful exploitation supplies kernel read/write primitives, and DarkSword has used the flaw as its privilege-escalation stage.
Summary
What happened
Kernel memory corruption in Apple iOS, iPadOS, macOS, tvOS, visionOS, and watchOS allows local users to write kernel memory or crash the system. XNU VFS contiguous I/O re-fetches a user mapping without confirming that it remains physically contiguous, so a mapping-swap race directs access to unrelated physical pages. A locally running malicious app must win the race; successful exploitation supplies kernel read/write primitives, and DarkSword has used the flaw as its privilege-escalation stage.
The record
- CVE
- CVE-2025-43520
- Published
- Dec 12, 2025
- Updated
- Dec 12, 2025
- Vendor
- Apple
- Product
- iOS and iPadOS
- Classifications
- CWE-120, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 1, 2025Exploitation reportedDarkSword iOS exploit chain
- Dec 12, 2025CVE publishedPublication date reported by the CVE source.
- Dec 12, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <18.7
- Affected versionversion=unspecified <26.1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- ClearSwordfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- DarkSword iOS exploit chainexploit chain
- CISA Known Exploited Vulnerabilities entryknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
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