Meshtastic vulnerabilities

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.

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.

Meshtastic is an open source mesh networking solution. The Meshtastic firmware (starting from version 2.5) introduces asymmetric encryption (PKI) for direct messages, but when the `pki_encrypted` flag is missing, the firmware silently falls back to legacy AES-256-CTR channel encryption. This was an intentional decision to maintain backwards compatibility. However, the end-user applications, like Web app, iOS/Android app, and applications built on top of Meshtastic using the SDK, did not have a way to differentiate between end-to-end encrypted DMs and the legacy DMs. This creates a downgrade attack path where adversaries who know a shared channel key can craft and inject spoofed direct messages that are displayed as if they were PKC encrypted. Users are not given any feedback of whether a direct message was decrypted with PKI or with legacy symmetric encryption, undermining the expected security guarantees of the PKI rollout. Version 2.7.15 fixes this issue.