CVE-2026-90150 in Linux
Summary
by MITRE • 09/17/2026
In the Linux kernel, the following vulnerability has been resolved:
pnfs/blocklayout: Fix device leaks on parse failure
bl_parse_concat() and bl_parse_stripe() allocate a child device array and then parse each child in turn. If parsing a child fails, the failed child is not counted in nr_children and the parent may be left with a children array that bl_free_device() will not release when nr_children is zero.
Release the failed child and the already parsed children before returning the error. Also make bl_free_device() release the child array whenever the children pointer is set, so that partially initialised concat or stripe devices are cleaned up correctly.
bl_parse_scsi() can also fail after assigning d->bdev_file and dropping the file reference. Clear the pointer after fput() so that an outer cleanup path does not put it again.
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Analysis
by VulDB Data Team • 09/17/2026
The Linux kernel vulnerability identified in the pnfs/blocklayout subsystem represents a critical resource management flaw involving improper handling of device structures during parsing operations. This issue primarily affects the block layout driver used for Parallel NFS (pNFS) implementations, where data is distributed across multiple storage devices to enhance performance and reliability. The core technical deficiency lies within the functions bl_parse_concat() and bl_parse_stripe(), which are responsible for constructing complex device configurations by aggregating child devices into parent structures such as concatenated or striped layouts. During this initialization process, these functions allocate an array of child device pointers and proceed to parse each individual child device sequentially. The fundamental flaw occurs when a parsing operation fails for any specific child device; in such scenarios, the failed child is excluded from the final count of valid children (nr_children), yet it remains present in the allocated parent's children array. Consequently, because nr_children is zero or does not account for this partially initialized state, the cleanup routine bl_free_device() incorrectly assumes there are no active children to release, leading to a memory leak where the child device structures and their associated resources remain allocated but unreachable by standard deallocation paths.
This resource leakage extends beyond simple memory consumption, potentially impacting system stability over time as repeated failures in parsing block layout configurations can exhaust kernel heap space or file descriptor limits depending on the specific resources held by each child device. The vulnerability is exacerbated by a secondary issue within bl_parse_scsi(), where a failure condition occurs after assigning d->bdev_file but before proper cleanup logic completes. In this sequence, the code drops the reference to the block device file using fput() but fails to clear the pointer in the data structure immediately afterward. This leaves a dangling or stale pointer that may be accessed by outer cleanup paths during error handling routines. If these outer paths attempt to release the same file reference again based on the uncleared pointer, it results in a double-free vulnerability, which can lead to kernel panics, memory corruption, or arbitrary code execution depending on how the allocator handles the freed object.
From a classification perspective, this set of flaws aligns with CWE-401 Missing Release of Memory after Effective Lifetime and CWE-415 Double Free, highlighting critical errors in resource lifecycle management within the Linux kernel's storage subsystem. The operational impact is significant for environments relying on pNFS block layouts, as attackers who can trigger parsing failures through malformed or maliciously crafted metadata could induce denial-of-service conditions via memory exhaustion or cause system crashes through double-free exploits. Furthermore, these vulnerabilities compromise the integrity of the storage stack by leaving orphaned resources that obscure debugging efforts and degrade overall system performance over extended uptime periods.
Mitigation strategies require immediate patching of the Linux kernel to include fixes for bl_parse_concat(), bl_parse_stripe(), and bl_parse_scsi(). The corrective logic involves ensuring that any child device allocated during parsing is explicitly released if subsequent steps fail, thereby preventing leaks regardless of whether nr_children reaches zero. Additionally, developers must enforce strict pointer nullification after fput() calls in scsi-related parsing routines to prevent double-free scenarios by outer cleanup handlers. System administrators should monitor for kernel updates addressing these specific block layout issues and consider implementing rigorous input validation on metadata inputs that trigger the pNFS configuration processes to reduce the attack surface available for triggering these code paths.