CVE-2026-53148 in Linux
Summary
by MITRE • 06/25/2026
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Clamp XDomain response data copy to allocation size
tb_xdp_properties_request() derives the per-packet copy length from the response header without checking that it fits in the previously allocated data buffer. A malicious peer can set its length field larger than the declared data_length, causing memcpy to write past the kcalloc allocation.
Clamp the per-packet copy length so that the cumulative offset never exceeds data_len.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 06/27/2026
The vulnerability resides within the thunderbolt subsystem of the Linux kernel, specifically in the tb_xdp_properties_request() function where improper bounds checking creates a potential buffer overflow condition. This flaw represents a classic case of inadequate input validation that can be exploited by malicious actors to overwrite adjacent memory regions. The vulnerability stems from the function's failure to verify that the length field specified in the response header aligns with the allocated buffer size, creating a scenario where a crafted packet can trigger an out-of-bounds write operation.
The technical execution of this vulnerability involves a malicious thunderbolt peer device deliberately setting the length field in its response header to exceed the data_length value that was previously allocated through kcalloc. When the kernel processes this malformed response, it attempts to copy data using memcpy with the oversized length parameter, resulting in memory corruption beyond the intended buffer boundaries. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, though it manifests as a heap-based overflow given the kcalloc allocation pattern. The flaw directly enables arbitrary code execution or system instability by allowing attackers to overwrite critical kernel data structures.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides a potential pathway for privilege escalation and system compromise within thunderbolt device communication contexts. Attackers with physical access to thunderbolt ports or those able to establish malicious thunderbolt connections can exploit this weakness to gain unauthorized access to kernel memory spaces. The vulnerability affects systems running Linux kernels that implement thunderbolt support and could enable attackers to execute malicious code with kernel privileges, potentially leading to complete system compromise. This risk is particularly concerning given the widespread adoption of thunderbolt interfaces in modern computing devices.
Mitigation strategies should focus on implementing proper bounds checking mechanisms within the thunderbolt subsystem to validate response header lengths against allocated buffer sizes before any memory operations occur. The solution involves clamping the per-packet copy length to ensure that cumulative offset calculations never exceed the declared data_len parameter, thereby preventing out-of-bounds memory writes. System administrators should ensure timely kernel updates that include patches addressing this specific vulnerability, while also implementing runtime monitoring for unusual thunderbolt communication patterns. Additionally, organizations should consider implementing hardware-level thunderbolt security features such as device authentication and access control policies to reduce the attack surface.
This vulnerability aligns with several ATT&CK techniques including privilege escalation through kernel exploits and defense evasion by corrupting system memory structures. The attack vector represents a sophisticated approach that leverages the trust model inherent in thunderbolt device communication, where malicious actors can exploit legitimate protocol handling to achieve unauthorized code execution. The remediation process requires careful consideration of backward compatibility while ensuring comprehensive protection against similar buffer overflow scenarios in related kernel subsystems. Security researchers should monitor for similar patterns in other kernel components that handle dynamic data allocation and copy operations, as this vulnerability demonstrates how seemingly minor input validation gaps can create significant security risks in kernel space operations.
The fix implemented through clamping mechanism directly addresses the root cause by establishing strict boundaries on memory copy operations based on pre-allocated buffer sizes. This approach prevents the cumulative offset from exceeding data_len while maintaining functional integrity of legitimate thunderbolt communications. The solution demonstrates the importance of defensive programming practices in kernel development where every memory operation must be validated against allocation boundaries to prevent exploitation. Given the critical nature of this vulnerability and its potential for system compromise, organizations should prioritize immediate patch deployment and conduct thorough security assessments of their thunderbolt-enabled systems.