Medium

CVE-2025-11617 — Buffer Over-read when receiving IPv6 packets with incorrect payload length in FreeRTOS-Plus-TCP

A missing validation check in FreeRTOS-Plus-TCP's IPv6 packet processing code can lead to an out-of-bounds read when receiving a IPv6 packet with incorrect payload lengths in the packet header. This issue only affects applications using IPv6. We recommend users upgrade to the latest version and ensure any forked or derivative code is patched to incorporate the new fixes.

Published Oct 10, 2025 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: AMZN

Low

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

EPSS 0.3% (30-day exploitation probability)+3
Technical severity (medium)+3

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

0.31%

ahead of 22% of scored CVEs · Oct 14, 2026

Affects

Amazon

Freertos-plus-tcp and 1 more

CVSS base

5.4

Medium · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

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.

Identify exposed assets running the affected vendor/product/version combinations (Amazon Freertos-plus-tcp, AWS FreeRTOS-Plus-TCP).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Amazon	Freertos-plus-tcp	≥ 4.0.0 and < 4.3.4	Vulnerable	NIST National Vulnerability Database
AWS	FreeRTOS-Plus-TCP	≥ 4.0.0 and < 4.3.4	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

Low

Privileges required

Low

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

None

Availability

Low

Every base score collected

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

Score	Version	Severity	Expl.	Impact	Scored by
5.3	CVSS 4.0	Medium	—	—	ff89ba41-3aa1-4d27-914a-91399e9639e5 via NIST National Vulnerability Database
5.3	CVSS 4.0	Medium	—	—	AMZN via CVE Program (cve.org) e CISA ADP
5.4	CVSS 3.1	Medium	2.8	2.5	ff89ba41-3aa1-4d27-914a-91399e9639e5 via NIST National Vulnerability Database
5.4	CVSS 3.1	Medium	—	—	AMZN via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L (score shown at the top: ff89ba41-3aa1-4d27-914a-91399e9639e5)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-126

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.31%

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
Affected products added · aws/freertos-plus-tcp
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 5.4
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Analyzed
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Oct 10, 2025 · AMZN

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

3 on the record

aws.amazon.com/security/security-bulletins/AWS-2025-023/
Vendor Advisory, vendor-advisory, NIST National Vulnerability Database
github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-wmjr-wm93-cvv2
Vendor Advisory, third-party-advisory, NIST National Vulnerability Database
github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.3.4
Release Notes, patch, product, NIST National Vulnerability Database

Elsewhere on this site

Amazon
every CVE for this vendor

CWE-126
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-7425 Out-of-Bounds Read in Router Advertisement Option Parser in FreeRTOS-Plus-TCP Apr 29, 2026
High CVE-2026-7426 Out-of-Bounds Write via Unsanitized Prefix Length in Router Advertisement Processing in FreeRTOS-Plus-TCP Apr 29, 2026
Medium CVE-2026-7422 MAC Address Validation Bypass in FreeRTOS-Plus-TCP IPv4 and IPv6 Packet Processing Apr 29, 2026
Medium CVE-2026-7423 Integer Underflow in ICMP Echo Reply Processing in FreeRTOS-Plus-TCP Apr 29, 2026
High CVE-2026-7424 Integer Underflow in DHCPv6 Sub-Option Parser in FreeRTOS-Plus-TCP Apr 29, 2026
Medium CVE-2025-11616 Buffer Over-read when receiving improperly sized ICMPv6 packets in FreeRTOS-Plus-TCP Oct 10, 2025

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 fixed version, patch or mitigation documented.
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-2025-11617 is "Buffer Over-read when receiving IPv6 packets with incorrect payload length in FreeRTOS-Plus-TCP", rated Medium. It affects Freertos-plus-tcp (Amazon); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.4 describes technical severity. EPSS 0.31% estimates the probability of exploitation in 30 days; neither replaces your asset context. 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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