Vulnerability Database

346,508

Total vulnerabilities in the database

CVE-2026-39461 — freebsd / freebsd

Stack-based Buffer Overflow

libcasper(3) communicates with helper processes via UNIX domain sockets, and uses the select(2) system call to wait for data to become available. However, it does not verify that its socket descriptor fits within select(2)'s descriptor set size limit of FD_SETSIZE (1024).

An attacker able to cause an application using libcasper(3) to allocate large file descriptors, e.g., by opening many descriptors and executing a program which is not careful to close them upon startup, may trigger stack corruption. If the target application runs with setuid root privileges, this could be used to escalate local privileges.

  • Published: May 21, 2026
  • Updated: May 22, 2026
  • CVE: CVE-2026-39461
  • Severity: High
  • Exploit:

CVSS v3:

  • Severity: High
  • Score: 8.8
  • AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/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-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-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

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.