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Meshtastic FirmwareOperating system · Meshtastic

CVE-2025-55293

CRITICAL · 9.8 CVSS v3.1 Published 2025-08-18
Fix available
A fix is available. Upgrade to 2.6.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Meshtastic is an open source mesh networking solution. Prior to v2.6.3, an attacker can send NodeInfo with a empty publicKey first, then overwrite it with a new key. First sending a empty key bypasses 'if (p.public_key.size > 0) {', clearing the existing publicKey (and resetting the size to 0) for a known node. Then a new key bypasses 'if (info->user.public_key.size > 0) {', and this malicious key is stored in NodeDB. This vulnerability is fixed in 2.6.3.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Meshtastic prior to v2.6.3, the NodeInfo handling logic has a flaw where sending an empty publicKey (size=0) first clears an existing publicKey for a known node, resetting its size to 0. Then sending a new key with a positive size bypasses validation checks because the prior size is now 0, allowing an attacker to inject a malicious publicKey into the NodeDB for a legitimate node.

MitigationUpgrade Meshtastic to v2.6.3 or later to obtain the patch that fixes the publicKey validation logic in NodeInfo handling.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Meshtastic FirmwareOperating system
Affected:< 2.6.3

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Meshtastic firmware version
    Connect to the Meshtastic device via serial, CLI (meshtastic --get firmware_version), or the Android/iOS app to retrieve the currently installed firmware version. Check the version string against the release notes for 2.6.3.
    Affected if The installed firmware version is any version prior to 2.6.3 (e.g., 2.6.2, 2.6.1, 2.5.x, etc.).
  2. Review NodeDB public key entries
    Use the Meshtastic CLI (meshtastic --nodes) or the mobile app to list all known nodes in the mesh network. Examine each node entry for the publicKey field.
    Affected if Any node in the NodeDB has a publicKey that you do not recognize, did not personally add, or that differs from keys you expect from known legitimate nodes in your mesh.
  3. Check for nodes with empty publicKey
    Review the same NodeDB output for any nodes that show an empty or blank publicKey field, particularly for nodes you know should have a valid key configured.
    Affected if A known node that previously had a valid publicKey now shows an empty or null publicKey, which may indicate the first stage of this attack (key clearing).
  4. Verify key ownership with out-of-band confirmation
    For each node in the NodeDB, independently verify the expected publicKey through a separate trusted channel (direct physical access, encrypted side channel, or prior documented key exchange). Compare the verified keys against what is stored in NodeDB.
    Affected if Any stored publicKey does not match the out-of-band verified key for that same node, indicating potential key substitution.

You are affected if your Meshtastic firmware is version 2.6.2 or earlier AND your NodeDB contains any unrecognized, blank, or mismatched publicKey entries for nodes in your mesh network.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.6.3 or later
Fixed in 2.6.3
Vendor patch github.com →
Interim mitigation

Upgrade Meshtastic to v2.6.3 or later to obtain the patch that fixes the publicKey validation logic in NodeInfo handling.

Recommended fix High confidence

Meshtastic Firmware v2.6.3 or later

  1. 1. Identify all Meshtastic devices running firmware versions prior to 2.6.3 in your mesh network
  2. 2. Obtain the latest Meshtastic firmware version 2.6.3 or later from the official Meshtastic releases
  3. 3. Connect each affected device to a computer with the Meshtastic flasher tool (Python CLI, ESP32 flashing tool, or supported hardware flasher)
  4. 4. Flash the updated firmware (version 2.6.3 or newer) to each device, ensuring stable power throughout the flashing process
  5. 5. After flashing, verify each device is running firmware version 2.6.3 or later using the Meshtastic client or device status command
  6. 6. Confirm the NodeDB has been updated and no empty publicKey entries exist by checking node information through the client

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Meshtastic Firmware Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-55293 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data