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CVE-2026-42566— Meshtastic: Malformed UTF-8 in User.long_name broadcast over LoRa causes mesh-wide client decode failure

Quick assessment

Affected
meshtastic firmware
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Meshtastic Meshtastic是Meshtastic社区的一款LoRa无线通信设备。 Meshtastic 2.7.23.b246bcd之前版本存在输入验证错误漏洞，该漏洞源于输入验证错误，可能导致通过iOS App管理时，一个带有畸形字符编码的User.long_name广播节点使其他无线电设备无法使用，进而导致BLE同步进入失败/重试循环，并丧失对受影响设备的控制。

CVSS 7.5 · High EPSS 0.49% · P40

Affected Version Matrix 1

VendorProduct Version RangeStatus
meshtastic firmware < 2.7.23.b246bcd affected
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I. Basic Information for CVE-2026-42566

Vulnerability Information
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Vulnerability Title
Meshtastic: Malformed UTF-8 in User.long_name broadcast over LoRa causes mesh-wide client decode failure
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
输入验证不恰当
Source: CVE Program / CVE List V5
Vulnerability Title
Meshtastic 输入验证错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Meshtastic Meshtastic是Meshtastic社区的一款LoRa无线通信设备。 Meshtastic 2.7.23.b246bcd之前版本存在输入验证错误漏洞，该漏洞源于输入验证错误，可能导致通过iOS App管理时，一个带有畸形字符编码的User.long_name广播节点使其他无线电设备无法使用，进而导致BLE同步进入失败/重试循环，并丧失对受影响设备的控制。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
meshtastic firmware < 2.7.23.b246bcd -

II. Public POCs for CVE-2026-42566

# POC Description Source Link Shenlong Link
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Qwen3.6-35B-A3B · 11249 chars
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III. Intelligence Information for CVE-2026-42566

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Patches & Fixes for CVE-2026-42566 (1)

Vendor Advisories for CVE-2026-42566 (1)

IV. Related Vulnerabilities

Same product: firmware
Same vendor: meshtastic
Same weakness: CWE-20

V. Comments for CVE-2026-42566

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