CVE-2025-21782 in Linux
Summary
by MITRE • 02/27/2025
In the Linux kernel, the following vulnerability has been resolved:
orangefs: fix a oob in orangefs_debug_write
I got a syzbot report: slab-out-of-bounds Read in orangefs_debug_write... several people suggested fixes, I tested Al Viro's suggestion and made this patch.
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Analysis
by VulDB Data Team • 05/25/2026
The vulnerability identified as CVE-2025-21782 resides within the Linux kernel's orangefs filesystem implementation, specifically in the orangefs_debug_write function where a buffer overflow condition has been addressed. This issue represents a classic out-of-bounds memory access flaw that could potentially allow malicious actors to exploit memory corruption vulnerabilities. The vulnerability was detected through automated testing systems and reported via syzbot, which identified a slab-out-of-bounds read condition during debugging operations. The orangefs filesystem is a distributed parallel file system designed for high-performance computing environments, and this vulnerability affects systems utilizing this particular filesystem implementation within the Linux kernel.
The technical flaw manifests as an out-of-bounds read operation within the orangefs_debug_write function, which processes debug write operations for the orangefs filesystem. This type of vulnerability falls under the CWE-125 category of Out-of-Bounds Read, where the code attempts to access memory locations beyond the allocated buffer boundaries. The vulnerability occurs when the debug write function processes input data without proper bounds checking, allowing an attacker to potentially read adjacent memory locations or cause system instability. The issue is particularly concerning because it involves kernel-level code execution, meaning that exploitation could lead to privilege escalation or system compromise. The root cause stems from insufficient validation of input parameters and buffer size calculations within the debug write functionality.
The operational impact of this vulnerability extends beyond simple memory corruption, as it represents a potential pathway for privilege escalation within systems running affected kernel versions. When exploited, the out-of-bounds read could expose sensitive kernel memory contents, potentially revealing stack canaries, kernel addresses, or other critical information that could aid in further exploitation attempts. Systems utilizing orangefs filesystems in production environments are at risk, particularly those with debug features enabled or systems that might be subject to malicious input through the debug interface. The vulnerability's exploitation potential aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation', and T1211 which covers 'Exploitation for Defense Evasion' when considering the potential for memory corruption attacks.
The resolution for this vulnerability involves implementing proper bounds checking within the orangefs_debug_write function to ensure that all memory accesses remain within allocated buffer boundaries. The fix, as implemented by Al Viro and subsequently tested, addresses the specific slab-out-of-bounds read condition that was being triggered during debugging operations. This patch demonstrates the importance of proper input validation in kernel code, particularly in debug interfaces that may be exposed to untrusted input. The mitigation approach follows standard security practices for preventing buffer overflow conditions and aligns with the principle of least privilege by ensuring that kernel debugging interfaces properly validate all input parameters. Organizations should prioritize applying this patch to systems running affected kernel versions to prevent potential exploitation of this memory corruption vulnerability.