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.

Meshtastic is an open source mesh networking solution. In affected firmware versions crafted packets over MQTT are able to appear as a DM in client to a node even though they were not decoded with PKC. This issue has been addressed in version 2.5.19 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the serialize() function in hono/cookie validates domain and path options against characters that corrupt Set-Cookie header syntax (;, \r, \n), but does not apply the same validation to sameSite and priority. An application that passes user-controlled input into either option may produce a Set-Cookie response header containing attacker-chosen additional attributes. This vulnerability is fixed in 4.12.21.