VDB-395675 · CVE-2026-58093 · WID-SEC-2026-3034

FreeBSD Kernel up to p2/p8/p12 TTY TIOCSCTTY ioctl handler race condition

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.4	$0-$5k	3.33

Summaryinfo

A vulnerability was found in FreeBSD Kernel up to p2/p8/p12. It has been rated as very critical. Impacted is the function TIOCSCTTY ioctl handler of the component TTY. The manipulation leads to race condition. This vulnerability is referenced as CVE-2026-58093. The attack can only be performed from a local environment. No exploit is available.

Detailsinfo

A vulnerability was found in FreeBSD Kernel up to p2/p8/p12. It has been rated as very critical. This issue affects the function TIOCSCTTY ioctl handler of the component TTY. The manipulation with an unknown input leads to a race condition vulnerability. Using CWE to declare the problem leads to CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

The TIOCSCTTY ioctl handler drops the tty lock in order to acquire the process tree lock. After reacquiring the tty lock, the handler did not revalidate the state of the terminal, and could proceed to link a terminal that was concurrently being destroyed to the calling process' session. An unprivileged local user can exploit this race condition to escalate privileges.

It is possible to read the advisory at security.freebsd.org. The identification of this vulnerability is CVE-2026-58093 since 06/29/2026. The exploitation is known to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/26/2026).

Upgrading to version p3, p9 or p13 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-3034). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

FreeBSD Project FreeBSD OS

Productinfo

Type

Operating System

Vendor

FreeBSD

Name

Kernel

Version

License

open-source

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel p3/p9/p13

Timelineinfo

06/29/2026 CVE reserved
08/26/2026 +58 days Advisory disclosed
08/26/2026 +0 days VulDB entry created
08/26/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: security.freebsd.org
Status: Confirmed

CVE: CVE-2026-58093 (🔒)
GCVE (CVE): GCVE-0-2026-58093
GCVE (VulDB): GCVE-100-395675
CERT Bund: WID-SEC-2026-3034 - FreeBSD Project FreeBSD OS: Mehrere Schwachstellen

Entryinfo

Created: 08/26/2026 07:59
Updated: 08/26/2026 15:33
Changes: 08/26/2026 07:59 (56), 08/26/2026 15:33 (7)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.