Stack Overflow Vulnerability in RPCSEC_GSS Implementation of FreeBSD Kernel

CVE-2026-4747

What is CVE-2026-4747?

CVE-2026-4747 is a significant stack overflow vulnerability present in the RPCSEC_GSS implementation within the FreeBSD kernel. The FreeBSD operating system is designed to provide a robust and secure platform for hosting various applications and services, including network file system (NFS) operations. This vulnerability arises due to a flaw in the way the kernel processes RPCSEC_GSS data packets. Specifically, a routine that validates incoming packets—by checking the signature—unsafely copies data into a stack buffer without ensuring that the buffer's size is adequate. This oversight creates a risk where a malicious client can trigger a stack overflow, potentially leading to remote code execution. Notably, attackers do not need prior authentication to exploit this vulnerability, broadening the potential attack surface for organizations depending on FreeBSD's NFS services.

Potential impact of CVE-2026-4747

1. Remote Code Execution: The most severe implication of CVE-2026-4747 is the ability for attackers to execute arbitrary code on the FreeBSD kernel. If successfully exploited, this could allow unauthorized parties to gain control over critical system functions, leading to severe security breaches.

2. Compromise of NFS Services: As this vulnerability is directly related to the FreeBSD NFS server operations, exploitation could jeopardize the integrity and availability of shared file systems. An attacker could manipulate or destroy data, disrupting business operations reliant on these services.

3. Increased Attack Surface: Given that exploitation does not require authentication, the vulnerability significantly increases the attack surface for FreeBSD systems operating in environments where untrusted users can send RPCSEC_GSS packets. Organizations may find themselves facing increased risks from both opportunistic and targeted attacks.

Human OS v1.0:
Ageing Is an Unpatched Zero-Day Vulnerability.

Remediate biological technical debt. Prime Ageing uses 95% high-purity SIRT6 activation to maintain genomic integrity and bolster systemic resilience.

Deploy the Patch →

References