CVE-2026-45256

Process termination via unchecked p_cansignal result

Published Jun 26, 2026 · Updated Jun 26, 2026

Improper privilege management in affected FreeBSD releases allows local users to terminate arbitrary processes through thr_kill2(2). In sys_thr_kill2(), the kernel calls p_cansignal() for a target thread but delivers the requested signal even when that permission check returns an error. Affected systems run 14.3-RELEASE before p15, 14.4-RELEASE before p6, or 15.0-RELEASE before p10; local users, including jailed users, need only discover global process and thread IDs to stop cross-user, host, or cross-jail processes, including critical daemons.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper privilege management in affected FreeBSD releases allows local users to terminate arbitrary processes through thr_kill2(2). In sys_thr_kill2(), the kernel calls p_cansignal() for a target thread but delivers the requested signal even when that permission check returns an error. Affected systems run 14.3-RELEASE before p15, 14.4-RELEASE before p6, or 15.0-RELEASE before p10; local users, including jailed users, need only discover global process and thread IDs to stop cross-user, host, or cross-jail processes, including critical daemons.

The record

CVE
CVE-2026-45256
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
The FreeBSD Project
Product
FreeBSD
Classifications
CWE-269, T1489
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=14.3-RELEASE <p15
  2. Affected versionversion=14.4-RELEASE <p6
  3. Affected versionversion=15.0-RELEASE <p10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The FreeBSD Project · FreeBSDversion=14.3-RELEASE <p15; version=14.4-RELEASE <p6; version=15.0-RELEASE <p10

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1489Service Stop

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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