Code execution via omitted JIT store barrier
Published Dec 17, 2025 · Updated Dec 17, 2025
Use-after-free in Apple WebKit across affected operating systems and Safari allows remote attackers to execute code via malicious web content. JavaScriptCore's DFG StoreBarrierInsertionPhase marks an escaped Phi node but not its transitive Upsilon inputs, omitting a barrier so concurrent garbage collection frees a reachable object. Exploitation requires processing attacker-controlled web content and winning a garbage-collection race; targeted exploitation was reported on iOS before 26.
Summary
What happened
Use-after-free in Apple WebKit across affected operating systems and Safari allows remote attackers to execute code via malicious web content. JavaScriptCore's DFG StoreBarrierInsertionPhase marks an escaped Phi node but not its transitive Upsilon inputs, omitting a barrier so concurrent garbage collection frees a reachable object. Exploitation requires processing attacker-controlled web content and winning a garbage-collection race; targeted exploitation was reported on iOS before 26.
The record
- CVE
- CVE-2025-43529
- Published
- Dec 17, 2025
- Updated
- Dec 17, 2025
- Vendor
- Apple
- Product
- iOS and iPadOS
- Classifications
- CWE-416, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 17, 2025CVE publishedPublication date reported by the CVE source.
- Dec 17, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
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 <26.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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.
Public exploit references
- jir4vv1t CVE-2025-43529 JavaScriptCore exploitfunctional · validated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- Apple report of targeted iOS exploitationreported exploitation
- CISA Known Exploited Vulnerabilities listingknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo