CVE-2026-71222 in Red Hat
Summary
by MITRE • 09/03/2026
A heap out-of-bounds read vulnerability was found in gfs2-utils. The ea_num_ptrs field from on-disk extended attribute metadata is consumed without bounds validation, causing a heap buffer over-read that may disclose sensitive memory contents or cause a crash when processing crafted GFS2 filesystem images.
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Analysis
by VulDB Data Team • 09/03/2026
The identified vulnerability resides within the gfs2-utils utility suite, specifically affecting components responsible for parsing and interpreting Extended Attribute (EA) metadata associated with the GFS2 file system format. This heap-based out-of-bounds read flaw is triggered by a failure to perform adequate bounds validation on the ea_num_ptrs field extracted from disk structures. In normal operation, this field indicates the number of pointers contained within an extended attribute entry. However, when processing maliciously crafted or corrupted GFS2 filesystem images where this value exceeds the actual allocated buffer size for pointer storage, the utility attempts to read memory locations beyond the bounds of the heap-allocated array. This lack of input validation allows the application to access arbitrary memory regions that are not intended to be part of the extended attribute data structure.
From a technical perspective, this vulnerability represents a classic instance of improper input handling leading to an out-of-bounds read condition. The root cause is the absence of checks ensuring that the number of pointers specified in the metadata does not exceed the physical limits of the buffer allocated during parsing. When such a crafted image is processed by tools like fsck.gfs2 or other utilities in the suite, the application reads past the end of the heap allocation. This behavior can lead to two primary adverse outcomes: information disclosure and denial of service. The out-of-bounds read may expose sensitive contents from adjacent memory regions, potentially leaking stack data, pointers to other objects, or even cryptographic keys if they reside nearby in memory. Alternatively, accessing unmapped or protected memory pages will result in a segmentation fault, causing the utility to crash abruptly and interrupting administrative operations such as file system checks or repairs.
The operational impact of this vulnerability is significant for administrators relying on gfs2-utils for maintenance tasks. Since these utilities are often run with elevated privileges during filesystem consistency checks, an exploit could potentially be leveraged in a local privilege escalation scenario if the attacker can influence the execution context or force the privileged process to read sensitive data into a location they control. Furthermore, the reliability of system administration tools is compromised, as unexpected crashes prevent successful completion of critical maintenance windows. This aligns with Common Weakness Enumeration CWE-125, which describes out-of-bounds read vulnerabilities where software reads past the end of an allocated buffer. Additionally, this behavior can be mapped to MITRE ATT&CK technique T1083, File and Directory Discovery, if the leaked memory contents are subsequently analyzed by an attacker to gather system information for further exploitation steps.
Mitigation strategies should focus on both immediate patching and long-term defensive coding practices. The primary remediation is to apply vendor-provided updates that correct the bounds checking logic within the gfs2-utils source code. Developers must ensure that any integer value derived from untrusted external sources, such as disk metadata, is validated against the maximum allowable size before being used for memory access operations. Implementing static analysis tools and fuzz testing during the software development lifecycle can help identify similar input validation gaps in other parts of the utility suite. For system administrators unable to immediately patch, restricting the execution of gfs2-utils to trusted users and avoiding the processing of untrusted or potentially corrupted filesystem images until patches are applied serves as a practical risk reduction measure. Regular auditing of file systems for corruption using safe tools can also reduce exposure to crafted inputs designed to trigger this specific memory access violation.