CVE-2026-53149 in Linux
Summary
by MITRE • 06/25/2026
In the Linux kernel, the following vulnerability has been resolved:
thunderbolt: Bound root directory content to block size
__tb_property_parse_dir() does not check that content_offset + content_len fits within block_len for the root directory case. When rootdir->length equals or exceeds block_len - 2, the entry loop reads past the allocated property block.
Add a bounds check after computing content_offset and content_len to reject directories whose content extends past the block.
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Analysis
by VulDB Data Team • 06/27/2026
This vulnerability exists in the linux kernel's thunderbolt subsystem where improper bounds checking in the __tb_property_parse_dir() function creates a potential for memory corruption through buffer overread conditions. The flaw specifically affects how the system handles root directory content within property blocks, where the code fails to validate that the computed content_offset plus content_len remains within the allocated block_len boundaries. When processing root directories where rootdir->length approaches or exceeds block_len minus two bytes, the parsing loop continues reading beyond the allocated memory region, potentially accessing invalid memory locations and causing system instability or arbitrary code execution.
The technical implementation of this vulnerability stems from a missing validation step in the property directory parsing logic that operates under the thunderbolt driver's management of device configuration properties. The function computes content_offset and content_len values without verifying whether their sum would exceed the available block length, creating a classic buffer overread scenario that can be exploited by malicious actors who craft specially formatted thunderbolt device configurations. This issue directly relates to common software security weaknesses categorized under cwe-129 and cwe-787 in the cwe dictionary, which address insufficient bounds checking and out-of-bounds reads respectively.
The operational impact of this vulnerability extends beyond simple memory corruption as it affects the entire thunderbolt subsystem's ability to safely process device property information. When exploited successfully, attackers could potentially cause kernel panics, system crashes, or more concerning arbitrary code execution within kernel space, compromising the integrity of systems that rely on thunderbolt connectivity for high-speed data transfer and device management. The vulnerability particularly affects systems with thunderbolt controllers that handle large root directory structures, making it relevant across various desktop and server platforms where thunderbolt technology is implemented.
Mitigation strategies should focus on implementing proper bounds checking within the thunderbolt driver's property parsing functions, specifically adding validation after content_offset and content_len computations to ensure their combined sum does not exceed block_len. System administrators should prioritize kernel updates that include the patched implementation which enforces these bounds checks before processing root directory content. Additionally, monitoring for unusual thunderbolt device behavior or configuration changes could help detect potential exploitation attempts. The fix aligns with standard security practices recommended in the mitre att&ck framework under defensive techniques related to input validation and memory safety controls, ensuring that kernel subsystems properly validate all input data before processing. Organizations should also consider implementing runtime protections such as kernel address space layout randomization and stack canaries to further reduce exploitability of similar vulnerabilities within the thunderbolt subsystem and other kernel components.