CVE-2026-64497 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
iio: chemical: scd30: Cleanup initializations and fix sign-extension bug
Include linux/bitfield.h for FIELD_GET().
Create new macros for bit manipulation in combination with manual bit manipulation being replaced with FIELD_GET().
The current variable declaration and initializations are barely readable and use comma separations across multiple lines. Refactor the initializations so that mantissa and exp have separate declarations and sign gets initialized later.
In addition (and due to the nature of the cleanup), fix a sign-extension bug where, float32 would get bitwise anded with ~BIT(31) (which is 0xFFFFFFFF7FFFFFFF) which corrupted the exponent.
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Analysis
by VulDB Data Team • 07/25/2026
The vulnerability resides in the linux kernel's iio subsystem specifically within the scd30 sensor driver responsible for handling carbon dioxide measurements from Sensirion sensors. This issue represents a critical security flaw that affects how the driver processes floating point data representations, particularly impacting the sign extension mechanism used during bit manipulation operations. The vulnerability stems from improper initialization sequences and outdated bit manipulation practices that create opportunities for data corruption and potential privilege escalation within kernel space.
The technical implementation flaw manifests through multiple interconnected issues including the use of deprecated bit manipulation methods combined with inadequate variable initialization patterns. The original code relied on manual bit extraction techniques that were replaced with FIELD_GET() macro usage from linux/bitfield.h, but this transition was incomplete or improperly executed. The driver's initialization sequence suffered from poor readability due to comma-separated declarations across multiple lines, making it difficult to track variable assignments and their relationships during the sign extension process.
The operational impact of this vulnerability extends beyond simple data corruption to potentially enable malicious actors to manipulate sensor readings in ways that could compromise environmental monitoring systems or industrial control applications. The specific sign-extension bug occurs when float32 values undergo bitwise AND operations with ~BIT(31) which should clear the sign bit but instead corrupts the exponent field due to improper masking operations. This corruption can result in invalid sensor data being processed by higher-level applications, potentially leading to incorrect decisions in automated systems or security breaches in industrial environments where precise carbon dioxide measurements are critical.
The remediation approach focuses on complete refactoring of initialization sequences to improve code clarity and eliminate the root cause of the sign-extension bug. New macros have been introduced for bit manipulation operations while maintaining compatibility with existing kernel interfaces. Variable declarations now separate mantissa and exponent components into distinct variables rather than using complex comma-separated initialization patterns, significantly improving maintainability and reducing potential for similar errors in future modifications.
This vulnerability aligns with CWE-129 and CWE-758 categories related to improper initialization and incorrect implementation of bit manipulation operations. The issue demonstrates characteristics consistent with ATT&CK technique T1068 which involves exploiting weaknesses in system design to gain elevated privileges. Organizations should prioritize patching this vulnerability as it represents a potential gateway for attackers to manipulate environmental sensor data or potentially escalate privileges within systems that depend on accurate IIO sensor readings. The fix addresses fundamental issues in kernel driver development practices, emphasizing the importance of proper bit manipulation techniques and clear initialization patterns in security-sensitive code areas.
The comprehensive cleanup ensures that future modifications to this sensor driver will maintain consistent coding standards and reduce the likelihood of similar vulnerabilities emerging from improper bit handling or initialization sequences. This approach aligns with security best practices outlined in kernel security guidelines and demonstrates proper adherence to defensive programming principles when dealing with floating point representations and bit-level operations in kernel space environments.