CVE-2026-42566
Received
Received - Intake
Buffer Overflow in Meshtastic Firmware
Vulnerability report for CVE-2026-42566, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-07-20
Last updated on: 2026-07-20
Assigner: GitHub, Inc.
Description
Description
Meshtastic is an open source mesh networking solution. Prior to version 2.7.23.b246bcd, a single node advertising a User.long_name that contains a malformed character encoding can render other radios unusable over BLE when managed through the iOS app. The malformed name does not need to be maliciously crafted — it can arise from ordinary buffer truncation and has been observed occurring naturally in the wild. At least one code path could place a null terminator in the middle of a multibyte sequence, leaving a malformed User.long_name in the node database. The problem surfaced downstream: the iOS app enforced encoding validation and therefore cannot parse a node database once it contains a poisoned entry. This caused BLE sync to enter a fail/retry loop, resulting in loss of control over the affected device. For a typical user managing their radio with the iOS app, the device becomes effectively unusable until the poisoned node ages out of the on-device database, or unless they have an alternate management path (e.g., the Python CLI, which can be used to identify and remove the offending entries manually). Because the malformed name propagates through the mesh, the temporary presence of a single affected node can degrade BLE management for iOS users across a wide geographical area for an extended period. Less technical users have no straightforward recovery path. Starting in version 2.7.23.b246bcd, the firmware has added input sanitization and regression tests demonstrating recovery for already-poisoned devices. The apps have also taken steps to ensure more graceful handling of malformed encoding sequences as well.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| meshtastic | meshtastic | to 2.7.23.b246bcd (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-20 | The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. |
