Buffer Copy No Size Check in Apache NimBLE <1.10 HCI Socket
CVE-2026-45811 Published on July 24, 2026
Apache NimBLE: Buffer overflow in socket HCI transport
Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in Apache NimBLE.
The HCI socket transport did not check whether a received HCI event would fit the configured event pool before copying it, allowing a buffer overflow. Severity is low: exploitation requires either a misconfigured pool size or a malicious/compromised controller on the other end of the HCI socket link, not over-the-air Bluetooth access.
This issue affects Apache NimBLE: through 1.9.0.
Users are recommended to upgrade to version 1.10.0, which fixes the issue.
Vulnerability Analysis
Weakness Type
What is a Classic Buffer Overflow Vulnerability?
The program copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. A buffer overflow condition exists when a program attempts to put more data in a buffer than it can hold, or when a program attempts to put data in a memory area outside of the boundaries of a buffer. The simplest type of error, and the most common cause of buffer overflows, is the "classic" case in which the program copies the buffer without restricting how much is copied. Other variants exist, but the existence of a classic overflow strongly suggests that the programmer is not considering even the most basic of security protections.
CVE-2026-45811 has been classified to as a Classic Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-45811
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Affected Versions
Apache Software Foundation Apache NimBLE:- Before and including 1.9.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.