firmware: Improper Neutralization of Special Elements
CVE-2024-51500 is a high-severity improper neutralization of special elements vulnerability in firmware from Meshtastic, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 2.5.6 as the first without the flaw, so updating firmware to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.42% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update firmware to 2.5.6 or a later version.
- Update Meshtastic Firmware to 2.5.6 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Meshtastic | firmware | < 2.5.6; before 2.5.6 | 2.5.6 |
| Meshtastic | Meshtastic Firmware | before 2.5.6 | 2.5.6 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 5.3 | Medium | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
Meshtastic firmware is a device firmware for the Meshtastic project. The Meshtastic firmware does not check for packets claiming to be from the special broadcast address (0xFFFFFFFF) which could result in unexpected behavior and potential for DDoS attacks on the network. A malicious actor could craft a packet to be from that address which would result in an amplification of this one message into every node on the network sending multiple messages. Such an attack could result in degraded network performance for all users as the available bandwidth is consumed. This issue has been addressed in release version 2.5.6. All users are advised to upgrade. There are no known workarounds for this vulnerability.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements
The product receives input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could be interpreted as control elements or syntactic markers when they are sent to a downstream component.
How developers prevent this class of flaw
- Developers should anticipate that special elements (e.g. delimiters, symbols) will be injected into input vectors of their product. One defense is to create an allowlist (e.g. a regular expression) that defines valid input according to the requirements specifications. Strictly filter any input that does not match against the allowlist. Properly encode your output, and quote any elements that have special meaning to the component with which you are communicating.
- Use and specify an appropriate output encoding to ensure that the special elements are well-defined. A normal byte sequence in one encoding could be a special element in another.
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
More Improper Neutralization of Special Elements vulnerabilities (CWE-138)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/meshtastic/firmware/security/advisories/GHSA-xfmq-5j3j-vgv8Third Party Advisory
Other vulnerabilities in firmware
- 10.0 Critical severity
- 7.5 High severity
- 8.2 High severity
- 9.8 Critical severity
- 8.0 High severity
- 8.3 High severity
Recent Improper Neutralization of Special Elements vulnerabilities
- 9.8 Critical severity
- 7.2 High severity
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