CVE Intelligence
High

CVE-2026-102551 — Improper verification of the source of a communication channel in FreeRTOS-Plus-TCP Router Advertisement handling

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.

Published Oct 16, 2026 · Updated Oct 16, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: AMZN

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Freertos
FreeRTOS-Plus-TCP
CVSS base
7.7
High · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Freertos FreeRTOS-Plus-TCP).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Freertos FreeRTOS-Plus-TCP ≤ 4.4.1 Vulnerable CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.2 CVSS 4.0 Critical — — ff89ba41-3aa1-4d27-914a-91399e9639e5 via NIST National Vulnerability Database
9.2 CVSS 4.0 Critical — — AMZN via CVE Program (cve.org) e CISA ADP
7.7 CVSS 3.1 High 2.2 5.5 ff89ba41-3aa1-4d27-914a-91399e9639e5 via NIST National Vulnerability Database
7.7 CVSS 3.1 High — — AMZN via CVE Program (cve.org) e CISA ADP
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L (score shown at the top: ff89ba41-3aa1-4d27-914a-91399e9639e5)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-940

Other CVEs with this weakness →

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Received → Awaiting Analysis
    Oct 16, 2026 · NIST National Vulnerability Database
  • Affected products added · freertos/freertos-plus-tcp
    Oct 16, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 16, 2026
  • CVSS changed · 7.7
    Oct 16, 2026 · NIST National Vulnerability Database
  • Source status changed · → Received
    Oct 16, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 16, 2026 · Alertas do Telegram
  • CVE published
    Oct 16, 2026 · AMZN

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 16, 2026 – Oct 16, 2026
  • 1× Official description updated · Oct 16, 2026 – Oct 16, 2026

References

3 on the record

Elsewhere on this site

Freertos
every CVE for this vendor
CWE-940
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-102552 Improper verification of the source of a communication channel in FreeRTOS-Plus-TCP DNS resolver 19h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-102551 is "Improper verification of the source of a communication channel in FreeRTOS-Plus-TCP Router Advertisement handling", rated High. It affects FreeRTOS-Plus-TCP (Freertos); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.7 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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