CVE-2026-74457 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
can: peak_usb: add bounds check for USB channel index
The channel control index ctrl_idx is derived from rx->len which comes directly from a device USB payload. The mask 0x0f allows values 0-15, but the array size of usb_if->dev[] is only 2. Values 2-15 cause heap
out-of-bounds read, eventually causing kernel panic in the IRQ context.
Add bounds checking for ctrl_idx before the array access in both pcan_usb_pro_handle_canmsg() and pcan_usb_pro_handle_error().
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel's peak_usb driver represents a critical heap out-of-bounds read condition that can lead to system instability and potential privilege escalation. This issue resides within the CAN (Controller Area Network) USB device driver implementation where the kernel fails to properly validate input data derived from external USB communications. The flaw manifests when processing USB channel control messages through the pcan_usb_pro_handle_canmsg() and pcan_usb_pro_handle_error() functions, creating a scenario where untrusted data directly influences memory access patterns.
The technical root cause stems from improper bounds validation of the ctrl_idx variable which originates from rx->len field within USB payload data. This field is populated directly from device-generated USB packets without adequate sanitization or verification against expected parameter ranges. The implementation applies a bitwise mask 0x0f which permits values between 0 and 15, however the underlying usb_if->dev[] array has a fixed size of only two elements. This fundamental mismatch creates a clear path for out-of-bounds memory access when ctrl_idx values exceed the valid array boundaries.
The operational impact of this vulnerability extends beyond simple data corruption, as it operates within interrupt context during USB message processing. When an attacker crafts malicious USB packets with appropriately sized rx->len fields, the kernel can experience heap corruption that ultimately results in kernel panic conditions. This represents a serious reliability issue since the kernel panic occurs in IRQ context, potentially leading to complete system crashes or denial of service conditions in embedded systems and automotive applications that rely on CAN bus communications.
From a cybersecurity perspective, this vulnerability aligns with CWE-129 Input Validation and Output Processing, specifically addressing improper bounds checking in array access operations. The flaw also maps to ATT&CK technique T1068, as it represents an uncontrolled memory access pattern that could be exploited by malicious actors to achieve privilege escalation. Additionally, the vulnerability falls under the broader category of kernel-level buffer overflows that can lead to information disclosure and system compromise.
The recommended mitigation involves implementing explicit bounds checking for ctrl_idx before any array access operations in both affected functions. This defensive programming approach ensures that array indices remain within valid ranges by validating against the actual array size of usb_if->dev[]. The fix should be implemented as a simple conditional check that verifies ctrl_idx is less than the array length before proceeding with memory operations, preventing the out-of-bounds access entirely while maintaining functional integrity of the USB CAN interface.
This vulnerability highlights the critical importance of input validation in kernel space code where untrusted data sources can directly influence memory management operations. The fix demonstrates proper defensive programming practices that should be applied throughout kernel drivers to prevent similar issues in other subsystems. Given the widespread use of CAN bus interfaces in automotive and industrial applications, addressing such vulnerabilities promptly is essential for maintaining system reliability and security across various deployment environments.