FreeBSD-SA-26:63.posixshm

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-26:63.posixshm Security Advisory The FreeBSD Project Topic: TOCTOU race in POSIX shared memory large page configuration Category: core Module: posixshm...

CVE-2026-49428 posixshm: system calls can incorrectly free memory of largepage objects

Certain system calls, such open2 with the OTRUNC flag set, and fspacectl2, could incorrectly free memory in largepage objects. These operations are not permitted on largepage objects, but the implementation did not verify this. An unprivileged local user can abuse the bug to access freed kernel...

CVE-2026-49428

In FreeBSD's posixshm module, open(2) with O_TRUNC and fspacectl(2) failed to verify whether operations are permitted on largepage objects, incorrectly freeing kernel memory. An unprivileged local user can read freed kernel memory and escalate privileges. Affected: all supported versions prior to...

CVE-2026-49428 posixshm: system calls can incorrectly free memory of largepage objects

Certain system calls, such open2 with the OTRUNC flag set, and fspacectl2, could incorrectly free memory in largepage objects. These operations are not permitted on largepage objects, but the implementation did not verify this. An unprivileged local user can abuse the bug to access freed kernel...

CVE-2026-49427 posixshm: largepage shared memory objects not explicitly wired

Pages belonging to largepage shared memory objects were not explicitly wired. When sendfile2 transmitted such an object with the SFNOCACHE flag, it freed the underlying pages after transmission even though existing mappings still referred to them. An unprivileged local user can abuse the bug to...

CVE-2026-49427

CVE-2026-49427 is a use-after-free vulnerability in FreeBSD's POSIX largepage shared memory objects (posixshm module). Pages in largepage objects were not explicitly wired, so when sendfile(2) transmitted such an object with the SF_NOCACHE flag, it freed underlying pages while existing mappings s...