FreeRTOS-Plus-TCP: Improper Verification of Source of a Communication Channel
CVE-2026-102551 is a high-severity improper verification of source of a communication channel vulnerability in FreeRTOS-Plus-TCP from FreeRTOS, with a CVSS 3.1 base score of 7.7 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected FreeRTOS-Plus-TCP versions: 4.4.1 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.27% 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
- Check which version of FreeRTOS-Plus-TCP you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on aws.amazon.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 |
|---|---|---|---|
| FreeRTOS | FreeRTOS-Plus-TCP | 4.4.1 and earlier | Not stated |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- LowPerformance or availability is reduced.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 9.2 | Critical | CNA |
| CVSS 3.1 | 7.7 | High | CNA |
Official description
Improper verification of the source of a communication channel in the IPv6 Router Advertisement handler in Amazon FreeRTOS-Plus-TCP before V4.4.2 might allow a remote third-party to influence an endpoint's IPv6 default gateway, on-link prefix, and address configuration via a crafted Router Advertisement. To remediate this issue, users should upgrade to version V4.4.2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Source of a Communication Channel
The product establishes a communication channel to handle an incoming request that has been initiated by an actor, but it does not properly verify that the request is coming from the expected origin.
How developers prevent this class of flaw
- Use a mechanism that can validate the identity of the source, such as a certificate, and validate the integrity of data to ensure that it cannot be modified in transit using an Adversary-in-the-Middle (AITM) attack. When designing functionality of actions in the URL scheme, consider whether the action should be accessible to all mobile applications, or if an allowlist of applications to interface with is appropriate.
More Improper Verification of Source of a Communication Channel vulnerabilities (CWE-940)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other vulnerabilities in FreeRTOS-Plus-TCP
- 8.1 High severity
Recent Improper Verification of Source of a Communication Channel vulnerabilities
- 7.4 High severity
- 8.8 High severity
- 9.6 Critical severity
- 8.8 High severity
- 9.3 Critical severity
- 7.5 High severity
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