Vulnerability Database

357,869

Total vulnerabilities in the database

CVE-2026-45256 — freebsd / freebsd

Improper Privilege Management

When used to deliver a signal to a specific thread, thr_kill2(2) called p_cansignal() to determine whether the operation was permitted but did not check the result before delivering the signal. The signal was sent even when the permission check failed. The system call returned the resulting error to the caller, but by then the signal had already been delivered.

The missing check allows an unprivileged local user who knows or can guess a target's process and thread IDs to send any signal to a process they would not normally be permitted to signal, including processes owned by other users or by root. The same check enforces jail boundaries, so a jailed process can signal processes on the host or in other jails. Thread IDs are allocated globally and sequentially, and so can be discovered by brute force with no visibility into the target.

An attacker can stop or terminate arbitrary processes, including critical system daemons, resulting in a Denial of Service (DoS).

  • Published: Jun 26, 2026
  • Updated: Jun 27, 2026
  • CVE: CVE-2026-45256
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v3:

  • Severity: Medium
  • Score: 5.5
  • AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWEs:

Software From Fixed in
freebsd / freebsd 14.3 14.3.x
freebsd / freebsd 14.3-p1 14.3-p1.x
freebsd / freebsd 14.3-p10 14.3-p10.x
freebsd / freebsd 14.3-p11 14.3-p11.x
freebsd / freebsd 14.3-p12 14.3-p12.x
freebsd / freebsd 14.3-p13 14.3-p13.x
freebsd / freebsd 14.3-p14 14.3-p14.x
freebsd / freebsd 14.3-p2 14.3-p2.x
freebsd / freebsd 14.3-p3 14.3-p3.x
freebsd / freebsd 14.3-p4 14.3-p4.x
freebsd / freebsd 14.3-p5 14.3-p5.x
freebsd / freebsd 14.3-p6 14.3-p6.x
freebsd / freebsd 14.3-p7 14.3-p7.x
freebsd / freebsd 14.3-p8 14.3-p8.x
freebsd / freebsd 14.3-p9 14.3-p9.x
freebsd / freebsd 14.4 14.4.x
freebsd / freebsd 14.4-p1 14.4-p1.x
freebsd / freebsd 14.4-p2 14.4-p2.x
freebsd / freebsd 14.4-p3 14.4-p3.x
freebsd / freebsd 14.4-p4 14.4-p4.x
freebsd / freebsd 14.4-p5 14.4-p5.x
freebsd / freebsd 14.4-rc1 14.4-rc1.x
freebsd / freebsd 15.0 15.0.x
freebsd / freebsd 15.0-p1 15.0-p1.x
freebsd / freebsd 15.0-p2 15.0-p2.x
freebsd / freebsd 15.0-p3 15.0-p3.x
freebsd / freebsd 15.0-p4 15.0-p4.x
freebsd / freebsd 15.0-p5 15.0-p5.x
freebsd / freebsd 15.0-p6 15.0-p6.x
freebsd / freebsd 15.0-p7 15.0-p7.x
freebsd / freebsd 15.0-p8 15.0-p8.x
freebsd / freebsd 15.0-p9 15.0-p9.x
freebsd / freebsd 15.1-rc2 15.1-rc2.x

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.