Vulnerability · Published Mar 26, 2026 · Assigned by freebsd
CVE-2026-4747Remote code execution via RPCSEC_GSS packet validation
High 8.8
In plain English
A high-severity stack buffer overflow in FreeBSD from FreeBSD. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 3.4% (higher than 89% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
Each RPCSEC_GSS data packet is validated by a routine which checks a signature in the packet. This routine copies a portion of the packet into a stack buffer, but fails to ensure that the buffer is sufficiently large, and a malicious client can trigger a stack overflow. Notably, this does not require the client to authenticate itself first. As kgssapi.ko's RPCSEC_GSS implementation is vulnerable, remote code execution in the kernel is possible by an authenticated user that is able to send packets to the kernel's NFS server while kgssapi.ko is loaded into the kernel. In userspace, applications which have librpcgss_sec loaded and run an RPC server are vulnerable to remote code execution from any client able to send it packets. We are not aware of any such applications in the FreeBSD base system.
Affected products (as reported)
Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H