Kernel use-after-free via page-list reinsertion
Published Aug 19, 2026 · Updated Aug 20, 2026
Use-after-free in FreeBSD allows local users to corrupt kernel memory via msync(MS_INVALIDATE) on unmanaged device mappings. In the VM device pager, msync(MS_INVALIDATE) invalidates a mapped fictitious page without removing it from the object's page list, and a later fault makes dev_pager_getpages() insert the same page again. Exploitation requires unprivileged local access to a device that exposes memory-mapped I/O; the corrupted list causes a double free during object teardown and stays within the fictitious-page pool, though FreeBSD notes possible privilege escalation.
Summary
What happened
Use-after-free in FreeBSD allows local users to corrupt kernel memory via msync(MS_INVALIDATE) on unmanaged device mappings. In the VM device pager, msync(MS_INVALIDATE) invalidates a mapped fictitious page without removing it from the object's page list, and a later fault makes dev_pager_getpages() insert the same page again. Exploitation requires unprivileged local access to a device that exposes memory-mapped I/O; the corrupted list causes a double free during object teardown and stays within the fictitious-page pool, though FreeBSD notes possible privilege escalation.
The record
- CVE
- CVE-2026-49418
- Published
- Aug 19, 2026
- Updated
- Aug 20, 2026
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 20, 2026Record 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=14.3-RELEASE <p16
- Affected versionversion=14.4-RELEASE <p7
- Affected versionversion=15.0-RELEASE <p11
- Affected versionversion=15.1-RELEASE <p1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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