CVE-2026-45815 in NimBLE
Summary
by MITRE • 07/24/2026
Reachable Assertion vulnerability in Apache NimBLE. A specially crafted ATT Read Multiple Variable Response (BLE_ATT_OP_READ_MULT_VAR_RSP) may trigger assert in ATT parser.
Severity is medium as this requires DUT to first send ATT Read Multiple Variable Request.
This issue affects Apache NimBLE: through 1.9.0.
Users are recommended to upgrade to version 1.10.0, which fixes the issue.
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Analysis
by VulDB Data Team • 07/24/2026
The vulnerability under discussion represents a reachable assertion failure within the Apache NimBLE Bluetooth Low Energy stack implementation, specifically targeting the ATT (Attribute Protocol) parser component. This security flaw manifests when a maliciously crafted ATT Read Multiple Variable Response packet is transmitted to a device running affected NimBLE versions. The issue stems from insufficient input validation within the ATT protocol handler, which fails to properly sanitize or validate the structure of incoming multiple variable response packets before processing them through internal assertion checks.
The technical exploitation requires a specific sequence of events where an attacker must first establish communication with the vulnerable device and have it send an ATT Read Multiple Variable Request packet. This prerequisite makes the vulnerability medium severity rather than critical, as it cannot be triggered remotely without prior device interaction or connection establishment. The assertion failure occurs during the parsing phase of the ATT protocol stack when processing the malformed response packet, potentially leading to denial of service conditions where the device may crash or become unresponsive due to the assertion violation.
From a cybersecurity perspective, this vulnerability aligns with CWE-617, which addresses reachable assertions in software implementations. The flaw demonstrates poor defensive programming practices within the NimBLE stack's protocol parsing logic, where assumptions about packet structure are not properly validated before assertion checks are executed. This particular issue affects all versions of Apache NimBLE through 1.9.0, indicating a significant window of exposure for systems utilizing this Bluetooth stack implementation.
The operational impact of this vulnerability extends beyond simple service disruption, as it represents a potential vector for attackers to compromise the availability of BLE-enabled devices in various IoT deployments. Devices that rely on NimBLE for wireless communication may experience unexpected crashes or restarts when processing maliciously crafted responses, particularly in environments where continuous connectivity is critical. The vulnerability's medium severity classification reflects the requirement for prior device interaction, but it still poses a meaningful risk to systems where attackers can establish communication channels with target devices.
Organizations utilizing Apache NimBLE stacks should prioritize upgrading to version 1.10.0 or later, which includes patches addressing this assertion failure. The fix likely involves enhanced input validation within the ATT parser component and proper handling of malformed multiple variable response packets. Security teams should also conduct thorough vulnerability assessments of their BLE-enabled device fleets to identify any systems running vulnerable NimBLE versions, particularly in industrial IoT deployments where device availability is paramount. This vulnerability serves as a reminder of the importance of robust input validation in protocol implementations and demonstrates how seemingly minor parser flaws can lead to significant availability concerns in embedded systems.
The ATT&CK framework categorizes this vulnerability under T1499.004, which addresses network denial of service attacks through protocol manipulation. The vulnerability's exploitation pattern aligns with techniques involving malformed packet injection targeting protocol stack components, making it relevant to defensive strategies focused on network traffic validation and anomaly detection in BLE environments.