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CVE-2026-2261— blocklistd(8) socket leak

Quick assessment

Affected
FreeBSD FreeBSD
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

FreeBSD是FreeBSD基金会的一套类Unix操作系统。 FreeBSD存在安全漏洞，该漏洞源于编程错误导致套接字描述符泄漏，可能使blocklistd失效并影响系统性能。

AI Predicted 5.9 Difficulty: Moderate EPSS 0.37% · P29
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I. Basic Information for CVE-2026-2261

Vulnerability Information
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Vulnerability Title
blocklistd(8) socket leak
Source: CVE Program / CVE List V5
Vulnerability Description
Due to a programming error, blocklistd leaks a socket descriptor for each adverse event report it receives. Once a certain number of leaked sockets is reached, blocklistd becomes unable to run the helper script: a child process is forked, but this child dereferences a null pointer and crashes before it is able to exec the helper. At this point, blocklistd still records adverse events but is unable to block new addresses or unblock addresses whose database entries have expired. Once a second, much higher number of leaked sockets is reached, blocklistd becomes unable to receive new adverse event reports. An attacker may take advantage of this by triggering a large number of adverse events from sacrificial IP addresses to effectively disable blocklistd before launching an attack. Even in the absence of attacks or probes by would-be attackers, adverse events will occur regularly in the course of normal operations, and blocklistd will gradually run out file descriptors and become ineffective. The accumulation of open sockets may have knock-on effects on other parts of the system, resulting in a general slowdown until blocklistd is restarted.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
对已超过有效生命周期的资源丧失索引
Source: CVE Program / CVE List V5
Vulnerability Title
FreeBSD 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
FreeBSD是FreeBSD基金会的一套类Unix操作系统。 FreeBSD存在安全漏洞，该漏洞源于编程错误导致套接字描述符泄漏，可能使blocklistd失效并影响系统性能。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
FreeBSD FreeBSD 15.0-RELEASE ~ p3 -

II. Public POCs for CVE-2026-2261

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III. Intelligence Information for CVE-2026-2261

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Same Patch Batch · FreeBSD · 2026-03-09 · 6 CVEs total

CVE-2026-3038 Local DoS and possible privilege escalation via routing sockets
CVE-2025-15547 Jail escape by a privileged user via nullfs
CVE-2025-15576 Jail chroot escape via fd exchange with a different jail
CVE-2025-14558 Remote code execution via ND6 Router Advertisements
CVE-2025-14769 ipfw denial of service

IV. Related Vulnerabilities

Same product: FreeBSD
Same vendor: FreeBSD
Same weakness: CWE-772

V. Comments for CVE-2026-2261

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