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.
Published: 2026-08-19
Score: 8.1 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability originates from an unchecked PRIV_KTRACE permission for users in a FreeBSD jail. A jailed root user never receives the required privileged flag for ktrace(2), so on a jail the root’s ktrace status can be altered by any unprivileged user granted delete or debug rights to the target process. This flaw allows an unprivileged user to change or disable ktrace monitoring for a root‑owned process, effectively bypassing the intended isolation and enabling the user to observe or interfere with the process. The weakness is a privilege validation error (CWE‑273), which can lead to unauthorized monitoring or manipulation of a jailed root instance, potentially leaking confidential information or destabilizing the environment.

Affected Systems

This issue affects FreeBSD systems running any jail configuration where unprivileged users are granted debug or inspection privileges on processes owned by the jailed root. No specific product version range is listed, so all FreeBSD releases susceptible to the privilege bypass are impacted until the patch is applied.

Risk and Exploitability

EPSS score of <1% indicates a low probability of exploitation in the wild. The CVSS score of 8.1 indicates high severity. However, the flaw involves a privileged escalation within a jail—a trusted boundary—where an attacker already present as an unprivileged user in the jail can exploit the bug. The vulnerability is not listed in CISA KEV catalog. A likely attack vector involves existing debug permissions to manipulate ktrace flags and gain information otherwise reserved for root.

Generated by OpenCVE AI on August 27, 2026 at 19:12 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the latest FreeBSD security patch that addresses the ktrace privilege validation issue.
  • Restrict unprivileged users in jails from having debug or delete permissions on processes where ktrace is used, or remove those permissions entirely.
  • Configure host‑level ktrace settings (e.g., sysctl) to enforce the privileged flag requirement or disable ktrace inside jails until the patch is applied.

Generated by OpenCVE AI on August 27, 2026 at 19:12 UTC.

Tracking

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Advisories

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History

Mon, 31 Aug 2026 19:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p10:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p11:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p6:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p7:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p8:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.0:p9:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:-:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:p1:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:rc2:*:*:*:*:*:*
cpe:2.3:o:freebsd:freebsd:15.1:rc3-p1:*:*:*:*:*:*

Thu, 27 Aug 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 19 Aug 2026 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Freebsd
Freebsd freebsd
Vendors & Products Freebsd
Freebsd freebsd

Wed, 19 Aug 2026 07:45:00 +0000

Type Values Removed Values Added
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.
Title ktrace(2) privilege incorrectly validated in jails
Weaknesses CWE-273
References

cve-icon MITRE

Status: PUBLISHED

Assigner: freebsd

Published:

Updated: 2026-08-27T15:54:55.678Z

Reserved: 2026-06-29T01:40:17.498Z

Link: CVE-2026-58086

cve-icon Vulnrichment

Updated: 2026-08-27T15:54:40.488Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-19T08:17:12.777

Modified: 2026-08-31T18:44:55.330

Link: CVE-2026-58086

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-27T19:15:03Z

Weaknesses
  • CWE-273

    Improper Check for Dropped Privileges