CVE-2026-42566

HighCVSS 7.5

Published: 20/07/2026(UTC)Updated: 18/08/2026(UTC)Translated: 25/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.28%

20th percentile - higher than 20% of all known CVEs

Summary

In Meshtastic prior to version 2.7.23.b246bcd, a single node advertising a User.long_name with malformed character encoding can render other radios unusable over BLE when managed through the iOS app. The issue arises from accidental null terminator placement in a multibyte sequence during buffer truncation, poisoning the node database.

Risk Assessment

For the organization, the risk is that an iOS-managed device becomes unusable due to a BLE sync fail/retry loop, requiring manual CLI intervention or waiting for the poisoned node to age out. This can disrupt network operations over a wide area for an extended period.

Recommendation

Immediately upgrade Meshtastic firmware to version 2.7.23.b246bcd or later, which includes input sanitization and regression tests. For already-poisoned devices, use the Python CLI to identify and remove offending entries.

Other vulnerabilities in Meshtastic

CVE-2026-44359Critical
The Meshtastic GitHub repository before version 2.7.21.1370b23 has a vulnerability in the main_matrix.yml workflow triggered by pull_request_target. Multiple jobs check out the attacker's fork code and execute it with access to repository secrets and elevated GITHUB_TOKEN permissions. No approval gate exists. Pull requests from external users with author_association: "NONE" automatically triggered CI. The workflow directly executes attacker-controlled files from the fork checkout. This could lead to supply chain compromise, runner compromise, or repository takeover. The fix is in version 2.7.21.1370b23.

Original NVD description (English source)

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.