FreeBSD kernel TTY race condition allows local privilege escalation
Original title: ZDI-26-838: FreeBSD Kernel TTY Race Condition Local Privilege Escalation Vulnerability
CVE-2026-58093 is rated CVSS 7.8 and requires low-privileged code execution before exploitation.
ZDI advisory ZDI-26-838 covers a race condition in the FreeBSD kernel TTY code that can let a local attacker escalate privileges. The attacker must first execute low-privileged code on the system. ZDI assigned CVSS 7.8 and CVE-2026-58093. No version range, patch, or exploitation status is stated.
Unconfirmed: Affected versions, a fix, and exploitation status are not stated.
- Tracked as CVE-2026-58093 and ZDI-26-838.
- ZDI assigned a CVSS rating of 7.8.
- The bug is a race condition in the kernel TTY code.
- The attacker must already run low-privileged code.
Impact: Local privilege escalation on the FreeBSD kernel
| Product | Affected |
|---|---|
| FreeBSD Kernel | — |
- CVEs
- CVE-2026-58093
- Products
- FreeBSD Kernel
- Organizations
- Zero Day Initiative
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-58093 | The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process tree lock | 7.0 | <1% |
From the original article
This vulnerability allows local attackers to escalate privileges on affected installations of FreeBSD Kernel. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.
zerodayinitiative.com
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