High severity · published Aug 26, 2026
CVE-2026-58093
Kernel use-after-free via tty ioctls
7.0
CVSS
0.1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.1% · higher than 1% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeBSD · FreeBSD
15.1-RELEASE before p3; 15.0-RELEASE before p13; 14.4-RELEASE before p9 · source: vendor, NVD
In the news
VulnerabilityHigh
ZDI-26-784: FreeBSD Kernel kqueue Use-After-Free Local Privilege Escalation Vulnerability
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 8.8. The following CVEs are assigned: CVE-2026-58093.
Oct 16, 2026·Zero Day Initiative
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-58093
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-58093
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:62.tty.asc
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