CyberSecBulletin
CVE-2026-58089NVD status: Analyzed

FreeBSD: Improper Check for Dropped Privileges

Published Updated By the CyberSecBulletin desk

CVE-2026-58089 is a high-severity improper check for dropped privileges vulnerability in FreeBSD, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions p3, p13, p9 as the first without the flaw, so updating FreeBSD to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update FreeBSD to p3 or p13 or p9, whichever matches your release line, or a later version.
  2. Read the advisory on security.freebsd.org for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
FreeBSDFreeBSD15.1-RELEASE up to, but not including, p3; 15.0-RELEASE up to, but not including, p13; 14.4-RELEASE up to, but not including, p9p3, p13, p9

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
LowA basic user account is enough.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).

Official description

When a process calls execve(2) to execute a setuid or setgid image, hwpmc(4) is supposed to detach PMCs owned by unprivileged processes. An inverted check meant that this scenario was not handled properly. An unprivileged local user who has attached PMCs to a process can continue monitoring it after the process executes a setuid or setgid binary, contrary to the intended policy.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Check for Dropped Privileges

The product attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded.

How developers prevent this class of flaw

  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
  • Check the results of all functions that return a value and verify that the value is expected.
  • In Windows, make sure that the process token has the SeImpersonatePrivilege(Microsoft Server 2003). Code that relies on impersonation for security must ensure that the impersonation succeeded, i.e., that a proper privilege demotion happened.

More Improper Check for Dropped Privileges vulnerabilities (CWE-273)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in FreeBSD

All FreeBSD vulnerabilities

Recent Improper Check for Dropped Privileges vulnerabilities

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