High severity · published Aug 19, 2026
CVE-2026-58086
ktrace(2) privilege incorrectly validated in jails
8.1
CVSS
0.4%
EPSS
No
On KEV
Description
As an inadvertent side effect of an unrelated code change, PRIV_KTRACE was always denied to a jailed root user. Tracing configured by a jailed root user was therefore not flagged as privileged.
An unprivileged user in a jail that has permission to debug the target process can modify the jailed root user's ktrace(2) flags, or disable tracing outright. A jailed root user therefore cannot reliably trace unprivileged processes.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 32% 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 p2; 15.0-RELEASE before p12 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-58086
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-58086
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:53.ktrace.asc
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