# CVE-2025-21608: Forged packets over MQTT can show up in direct messages in Meshtastic firmware

> Attackers can forge MQTT packets to inject fake direct messages into Meshtastic nodes, bypassing cryptographic verification. Users should upgrade firmware.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 18 Feb 2025
- **Updated:** 19 Feb 2025
- **Also known as:** GHSA-c967-qc39-3hf5

## What is CVE-2025-21608?

CVE-2025-21608 is a medium-severity missing authorization vulnerability in meshtastic firmware, published on 18 Feb 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

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.

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere)

## Which versions are affected by CVE-2025-21608?

It affects 1 product.


Products: Meshtastic Meshtastic Firmware.

## How do I fix CVE-2025-21608?

No fix has been published for CVE-2025-21608 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-21608 being exploited?

There is no known exploitation of CVE-2025-21608 in the wild and no public exploit code.

## Other vulnerabilities in meshtastic firmware

- [CVE-2025-52464](https://insights.sbomify.com/CVE-2025-52464/): Meshtastic Repeated Public and Private Keypairs (critical 9.5)
- [CVE-2025-55293](https://insights.sbomify.com/CVE-2025-55293/): Meshtastic allows crafting of specific NodeInfo packets that overwrite any publicKey saved in the NodeDB (critical 9.4)
- [CVE-2025-24797](https://insights.sbomify.com/CVE-2025-24797/): Meshtastic incorrectly hands malformed packets leads to controlled buffer overflow (critical 9.4)
- [CVE-2025-55292](https://insights.sbomify.com/CVE-2025-55292/): In Meshtastic, an attacker can spoof licensed amateur flag for a node (high 8.2)
- [CVE-2024-47078](https://insights.sbomify.com/CVE-2024-47078/): Meshtastic firmware Authentication/Authorization Bypass via MQTT (high 8.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-21608 and fix it if it is affected.

What it is: CVE-2025-21608 is a medium-severity missing authorization vulnerability in meshtastic firmware, published on 18 Feb 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2025-21608 in the wild and no public exploit code.

Affected product: meshtastic firmware. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-21608/ (Markdown: https://insights.sbomify.com/CVE-2025-21608/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21608
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21608
- OSV: https://osv.dev/vulnerability/CVE-2025-21608

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21608/
Summaries are generated and may contain mistakes; the official description above is the record.