Use-after-free in FreeBSD - CVE-2026-49427
Published: July 1, 2026
Vulnerability identifier: #VU136014
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-49427
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: FreeBSD Foundation
Affected software:
FreeBSD
FreeBSD
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to use-after-free in POSIX largepage shared memory objects when transmitting such an object with sendfile(2) using the SF_NOCACHE flag. A local user can send a largepage shared memory object through sendfile(2) with the SF_NOCACHE flag to escalate privileges.
Existing mappings can continue to refer to the freed pages after transmission.
How to mitigate CVE-2026-49427
Install security update from vendor's website.