CVE Intelligence
Critical Memory corruption

CVE-2026-103415 — Out-of-bounds Write in Eclipse Foundation NetX Duo

When a TLS 1.3 client processes a HelloRetryRequest, it copies the server's cookie into its second ClientHello without checking that the cookie fits in the outgoing packet. Both the length and the contents of that cookie come from the peer, and the write happens before certificate authentication completes, so a malicious or compromised server can overwrite memory past the caller supplied TLS packet buffer without presenting a certificate. Only the client path is affected.

Published Oct 14, 2026 · Updated Oct 15, 2026 · Sources: CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database · CNA: eclipse

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 (critical)+10

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
0.28%
ahead of 20% of scored CVEs · Oct 15, 2026
Affects
Eclipse Foundation
NetX Duo
CVSS base
9.3
Critical · 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 (Eclipse Foundation NetX Duo).
  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 matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Eclipse Foundation NetX Duo ≤ 6.5.1.202602 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
Attack requirements
None
Privileges required
None
User interaction
None
Scope
X
Confidentiality (vulnerable system)
High
Integrity (vulnerable system)
High
Availability (vulnerable system)
High
Confidentiality (subsequent)
None
Integrity (subsequent)
None
Availability (subsequent)
None

Every base score collected

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

ScoreVersionSeverityExpl.ImpactScored by
9.3 CVSS 4.0 Critical — — emo@eclipse.org via NIST National Vulnerability Database
9.3 CVSS 4.0 Critical — — eclipse via CVE Program (cve.org) e CISA ADP
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X (score shown at the top: emo@eclipse.org)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-787 · Out-of-bounds Write

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).
  • Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Timeline

What happened to this CVE, newest first.

  • 2026
  • Source status changed · Received → Awaiting Analysis
    Oct 15, 2026 · NIST National Vulnerability Database
  • Source status changed · Published → Received
    Oct 14, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 14, 2026
  • CVSS changed · 9.3
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • Record created in this database
    Oct 14, 2026 · CVE Program (cve.org) e CISA ADP
  • CVE published
    Oct 14, 2026 · eclipse

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 14, 2026 – Oct 14, 2026

References

2 on the record

Elsewhere on this site

Eclipse Foundation
every CVE for this vendor
Memory corruption
same class
CWE-787
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-106465 Authentication Bypass by Spoofing in Eclipse Foundation NetX Duo 1d
  • CVE-2026-106464 Out-of-bounds Read in Eclipse Foundation NetX Duo 1d
  • CVE-2026-102717 MQTT WebSocket setter ABI mismatch may disclose memory or cause a crash 15d
  • CVE-2026-102759 NetX Secure TLS accepts an empty application-data record without verifying its message… 16d
  • CVE-2026-102758 The `_nx_secure_x509_asn1_tlv_block_parse()` function parses ASN.1 TLV… 16d
  • CVE-2026-102760 Use After Free in Eclipse Foundation NetX Duo 16d

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 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-2026-103415 is "Out-of-bounds Write in Eclipse Foundation NetX Duo", rated Critical. It affects NetX Duo (Eclipse Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.3 describes technical severity. EPSS 0.28% 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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