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ZDI-26-785: FreeBSD Kernel Shared Memory Time-Of-Check Time-Of-Use Local Privilege Escalation Vulnerability

FreeBSD · CVE-2026-58094 ZDI-26-785
0 news outlets0 CERTs and agencies0 researchers

What is it?

The FIOSSHMLPGCNF ioctl(2) operation configures the page size for a largepage shared memory object. This is intended to be used immediately after creating the object, before any memory is allocated for the object. The handler checked whether a page size had already been configured without holding the rangelock. Two concurrent callers could both observe an unconfigured object and set conflicting page sizes, leaving the object in an inconsistent state. An unprivileged local user can exploit this race to escalate privileges.

Evidence

Research (1)

Exploitation

  • Public proof of concept
  • Exploited in the wild
  • Listed as known exploited
CVSS
7.8
EPSS
0.1%
First seen
6 d ago
Status
confirmed

All FreeBSD vulnerabilities