CVE-2025-48768 Overview
A Release of Invalid Pointer or Reference vulnerability (CWE-763) was discovered in the fs/inode/fs_inoderemove code of Apache NuttX RTOS. This vulnerability allows an attacker to trigger root filesystem inode removal, which can lead to a debug assert trigger (disabled by default), NULL pointer dereference, or a Denial of Service condition. The impact varies depending on the target architecture and system configuration.
Critical Impact
Network-accessible filesystem services with write access (such as FTP) are vulnerable to Denial of Service attacks through improper inode removal handling.
Affected Products
- Apache NuttX RTOS versions 10.0.0 through 12.9.x
- Systems exposing filesystem-based services with write access over the network
- FTP servers running on vulnerable Apache NuttX versions
Discovery Timeline
- 2026-01-01 - CVE-2025-48768 published to NVD
- 2026-01-06 - Last updated in NVD database
Technical Details for CVE-2025-48768
Vulnerability Analysis
This vulnerability resides in the filesystem inode management code of Apache NuttX RTOS, specifically within the fs_inoderemove function. The flaw allows for the removal of the root filesystem inode, which should be protected from deletion. When exploited, this leads to an invalid pointer state that the system fails to properly handle.
The vulnerability is exploitable over the network, requiring low privileges (authenticated access) to trigger. The attack requires no user interaction and impacts system availability without affecting confidentiality or integrity. Systems running filesystem-based services exposed to the network, particularly FTP services with write access, are most at risk.
Root Cause
The root cause of this vulnerability is improper validation in the fs/inode/fs_inoderemove code path. The function fails to adequately protect the root filesystem inode from removal operations, allowing an attacker with write access to trigger invalid pointer states. This represents a classic Release of Invalid Pointer or Reference condition where the code releases or dereferences memory that should not be accessible.
Attack Vector
The vulnerability is exploitable through network-accessible filesystem services that provide write access. An authenticated attacker can manipulate filesystem operations to trigger the root inode removal, causing one of three outcomes depending on system configuration:
- Debug Assert Trigger - If debug assertions are enabled, the system will halt at the assert condition
- NULL Pointer Dereference - The resulting invalid pointer state leads to NULL pointer access, with behavior varying by target architecture
- Denial of Service - In all cases, the system becomes unavailable due to the corrupted filesystem state
The attack is particularly concerning for IoT and embedded devices running Apache NuttX that expose FTP or similar network services, as these devices may be difficult to recover without physical access.
Detection Methods for CVE-2025-48768
Indicators of Compromise
- Unexpected system crashes or reboots in Apache NuttX-based devices
- NULL pointer dereference errors in system logs related to filesystem operations
- Debug assertion failures in fs/inode/fs_inoderemove if assertions are enabled
- Filesystem corruption or unavailability following network filesystem access
Detection Strategies
- Monitor for anomalous filesystem operations through network services like FTP
- Implement logging for inode removal operations in Apache NuttX systems
- Deploy network intrusion detection rules to identify suspicious FTP commands targeting root filesystem structures
- Review system logs for crash patterns associated with filesystem inode operations
Monitoring Recommendations
- Enable verbose logging for filesystem operations on exposed Apache NuttX services
- Implement network traffic analysis for FTP and other filesystem services
- Set up alerting for unexpected device reboots or service interruptions
- Monitor for patterns of filesystem manipulation attempts from authenticated users
How to Mitigate CVE-2025-48768
Immediate Actions Required
- Upgrade Apache NuttX RTOS to version 12.10.0 or later immediately
- Restrict network access to filesystem-based services until patching is complete
- Disable or limit write access on network-exposed filesystem services where possible
- Implement network segmentation to reduce exposure of vulnerable embedded devices
Patch Information
Apache has released version 12.10.0 of NuttX RTOS which addresses this vulnerability. The fix is available through the official GitHub pull request #16437. Users should upgrade to version 12.10.0 or later to fully remediate this issue.
For detailed information about the security fix, refer to the Apache Mailing List announcement and the Openwall OSS Security disclosure.
Workarounds
- Disable network-exposed filesystem services (FTP, etc.) until the patch can be applied
- Implement strict access controls limiting which users can access filesystem services
- Deploy network-level restrictions (firewall rules, VPN requirements) to limit access to vulnerable services
- Consider enabling debug assertions temporarily to halt on exploitation attempts rather than allowing undefined behavior
# Configuration example - Restrict FTP access via firewall
# Block external FTP access to NuttX devices until patched
iptables -A INPUT -p tcp --dport 21 -s ! 10.0.0.0/8 -j DROP
# Alternatively, disable FTP service entirely in NuttX configuration
# In defconfig, disable CONFIG_FTPD to remove FTP server functionality
# CONFIG_FTPD is not set
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
