CVE-2026-23059 in Linux
Summary
by MITRE • 02/04/2026
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Sanitize payload size to prevent member overflow
In qla27xx_copy_fpin_pkt() and qla27xx_copy_multiple_pkt(), the frame_size reported by firmware is used to calculate the copy length into item->iocb. However, the iocb member is defined as a fixed-size 64-byte array within struct purex_item.
If the reported frame_size exceeds 64 bytes, subsequent memcpy calls will overflow the iocb member boundary. While extra memory might be allocated, this cross-member write is unsafe and triggers warnings under CONFIG_FORTIFY_SOURCE.
Fix this by capping total_bytes to the size of the iocb member (64 bytes) before allocation and copying. This ensures all copies remain within the bounds of the destination structure member.
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Analysis
by VulDB Data Team • 04/30/2026
The vulnerability identified as CVE-2026-23059 resides within the Linux kernel's SCSI subsystem, specifically affecting the qla2xxx driver that manages QLogic Fibre Channel host bus adapters. This issue manifests in the functions qla27xx_copy_fpin_pkt() and qla27xx_copy_multiple_pkt() where the driver processes firmware-reported frame sizes during Fibre Channel protocol handling. The flaw represents a classic buffer overflow condition that occurs when the reported frame size exceeds the allocated buffer space within the driver's internal data structures, creating a potential pathway for memory corruption and system instability.
The technical implementation of this vulnerability stems from improper bounds checking within the driver's frame processing logic. The driver maintains a fixed-size 64-byte array named iocb within the purex_item structure to store incoming frame data. When firmware reports a frame_size parameter that exceeds this 64-byte limit, the code proceeds to perform memcpy operations that write beyond the allocated array boundaries. This cross-member memory corruption violates fundamental memory safety principles and triggers kernel security mechanisms such as CONFIG_FORTIFY_SOURCE, which is designed to detect and prevent such buffer overflow conditions. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a direct violation of secure coding practices regarding buffer size validation.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially enable privilege escalation and system compromise. An attacker who can manipulate the firmware to report oversized frame sizes could cause the kernel to write beyond intended memory boundaries, potentially corrupting adjacent data structures or executing arbitrary code within kernel space. This represents a significant security risk in environments where untrusted storage networks or malicious firmware could be present. The vulnerability affects systems running Linux kernels with QLogic Fibre Channel adapters, particularly those utilizing the qla2xxx driver for SCSI communication, making it relevant to enterprise storage infrastructure and data center environments where such hardware is prevalent.
Mitigation strategies for CVE-2026-23059 should prioritize immediate kernel updates from vendors that include the patched version of the qla2xxx driver. The fix implemented addresses the core issue by enforcing strict bounds checking that caps the total_bytes parameter to exactly 64 bytes before any memory allocation or copying operations occur. This defensive programming approach ensures that all memory operations remain within the defined structure boundaries and prevents the overflow condition from occurring. System administrators should also implement monitoring for kernel security warnings related to CONFIG_FORTIFY_SOURCE and consider additional network segmentation measures to limit exposure to potentially malicious firmware updates. The solution aligns with ATT&CK technique T1068 by preventing local privilege escalation through memory corruption vulnerabilities, and follows the principle of least privilege by ensuring proper bounds checking in kernel memory operations. Organizations should verify their kernel versions and confirm that the specific patch addressing this vulnerability has been applied to maintain system integrity and prevent exploitation.