Kernel stack disclosure via uninitialized kevent32 copyout
Published Aug 19, 2026 · Updated Aug 19, 2026
Information disclosure in FreeBSD allows local users to read uninitialized kernel stack data via compat32 kevent() translation. In sys/compat/freebsd32/freebsd32_misc.c, freebsd32_kevent_copyout() used a stack array of struct kevent32 without zero-initializing it before translating and copying fields for return to user space. Exposure requires local execution on affected amd64 or arm64 systems with 32-bit compatibility support enabled, and the published impact is limited to disclosure of a small amount of kernel memory.
Summary
What happened
Information disclosure in FreeBSD allows local users to read uninitialized kernel stack data via compat32 kevent() translation. In sys/compat/freebsd32/freebsd32_misc.c, freebsd32_kevent_copyout() used a stack array of struct kevent32 without zero-initializing it before translating and copying fields for return to user space. Exposure requires local execution on affected amd64 or arm64 systems with 32-bit compatibility support enabled, and the published impact is limited to disclosure of a small amount of kernel memory.
The record
- CVE
- CVE-2026-49425
- Published
- Aug 19, 2026
- Updated
- Aug 19, 2026
- Vendor
- The FreeBSD Project
- Product
- FreeBSD
- Classifications
- Unavailable
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Aug 19, 2026CVE publishedPublication date reported by the CVE source.
- Aug 19, 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
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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