CVE-2025-38089

MEDIUM

Linux Kernel - NULL Pointer Dereference in RPC Server Authentication

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2025-38089. PoCs published by keymaker-arch.

AI-analyzed exploit summary This PoC exploits CVE-2025-38089, a kernel null pointer dereference in the Linux NFS server's SUNRPC code path, leading to a DoS via a crafted RPC request. The exploit establishes a TCP handshake and sends a malformed NFSv4 EXCHANGE_ID packet to trigger the crash.

Description

In the Linux kernel, the following vulnerability has been resolved: sunrpc: handle SVC_GARBAGE during svc auth processing as auth error tianshuo han reported a remotely-triggerable crash if the client sends a kernel RPC server a specially crafted packet. If decoding the RPC reply fails in such a way that SVC_GARBAGE is returned without setting the rq_accept_statp pointer, then that pointer can be dereferenced and a value stored there. If it's the first time the thread has processed an RPC, then that pointer will be set to NULL and the kernel will crash. In other cases, it could create a memory scribble. The server sunrpc code treats a SVC_GARBAGE return from svc_authenticate or pg_authenticate as if it should send a GARBAGE_ARGS reply. RFC 5531 says that if authentication fails that the RPC should be rejected instead with a status of AUTH_ERR. Handle a SVC_GARBAGE return as an AUTH_ERROR, with a reason of AUTH_BADCRED instead of returning GARBAGE_ARGS in that case. This sidesteps the whole problem of touching the rpc_accept_statp pointer in this situation and avoids the crash.

Exploits (1)

nomisec WORKING POC 8 stars
by keymaker-arch · poc
https://github.com/keymaker-arch/NFSundown

This PoC exploits CVE-2025-38089, a kernel null pointer dereference in the Linux NFS server's SUNRPC code path, leading to a DoS via a crafted RPC request. The exploit establishes a TCP handshake and sends a malformed NFSv4 EXCHANGE_ID packet to trigger the crash.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: Linux kernel NFS server (versions 6.3 to 6.15)
No auth needed
Prerequisites: Network access to vulnerable NFS server · Ability to send TCP packets to port 2049
devstral-2 · analyzed Feb 16, 2026 Full analysis →

Scores

CVSS v3 5.5
EPSS 0.0005
EPSS Percentile 16.1%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-476
Status published
Products (18)
linux/Kernel 6.13.0 - 6.15.4linux
linux/Kernel 6.4.0 - 6.6.95linux
linux/Kernel 6.7.0 - 6.12.35linux
Linux/Linux < 6.4
Linux/Linux 29cd2927fb914cc53b5ba4f67d2b74695c994ba4 - 353e75b55e583635bf71cde6abcec274dba05edd
Linux/Linux 29cd2927fb914cc53b5ba4f67d2b74695c994ba4 - 599c489eea793821232a2f69a00fa57d82b0ac98
Linux/Linux 29cd2927fb914cc53b5ba4f67d2b74695c994ba4 - 94d10a4dba0bc482f2b01e39f06d5513d0f75742
Linux/Linux 29cd2927fb914cc53b5ba4f67d2b74695c994ba4 - c90459cd58bb421d275337093d8e901e0ba748dd
Linux/Linux 6.12.35 - 6.12.*
Linux/Linux 6.15.4 - 6.15.*
... and 8 more
Published Jun 30, 2025
Tracked Since Feb 18, 2026