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HPE Instant On EUVDEUVD-2026-89340

| CVE-2026-76721 CRITICAL
Buffer Overflow (CWE-119)
2026-09-29 hpe GHSA-pw85-jqmm-v352
9.8
CVSS 3.1 · Vendor: hpe
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach exposed Instant On interface over network
  2. Delivery
    Send crafted oversized request
  3. Exploit
    Overflow buffer in affected interface
  4. Execution
    Hijack control flow
  5. Impact
    Execute arbitrary code as privileged user

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK

2 techniques across 2 tactics: Execution, Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

No special conditions in the base case - remote unauthenticated exploitation (AV:N/AC:L/PR:N/UI:N) is possible against the affected interface of HPE Networking Instant On firmware version ≤3.4.1.0. The practical prerequisite is network reachability to the vulnerable interface: an attacker must be able to send traffic to the exposed management or service interface of the Instant On access point/switch. Exploitation is LIMITED by device version (fixed in a version above 3.4.1.0 per the HPE advisory) and by network exposure - devices whose vulnerable interface is not reachable from the attacker's network segment (e.g., not internet-exposed and segmented from untrusted LAN) reduce realistic risk. The exact interface, port, and protocol are not specified in the provided data and should be confirmed against HPE advisory hpesbnw05150en_us.

Impact

This is a genuine high-priority issue, not a high-CVSS-but-low-real-risk case. The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, score 9.8) describes the worst-case remotely reachable, unauthenticated, no-interaction condition, and the vendor-confirmed description matches it exactly: an unauthenticated remote attacker triggers a buffer overflow to execute arbitrary code as a privileged user on the underlying OS. Every impact metric is High and complexity is Low, so a single reachable request could yield privileged RCE. Signals that RAISE priority: HPE (the vendor) is the reporting source, a patch/advisory is referenced (hpesbnw05150en_us), and the affected component is a network-facing management/data-plane interface. Signals that TEMPER urgency: EPSS score is not provided, the CVE is NOT listed in CISA KEV, and no public proof-of-concept is identified - so there is no confirmed active exploitation or automated weaponization yet. The absence of EPSS/KEV/POC data means exploitation likelihood cannot be quantified from these inputs, but the combination of unauthenticated network RCE in a networking appliance historically attracts rapid attacker interest once details or patches are analyzed. CWE is listed as N/A in the feed although the tags and description clearly indicate a buffer overflow (memory-corruption class).

Exploit ScenarioDerived

A remote attacker with network reachability to an internet- or LAN-exposed HPE Networking Instant On device (or its management interface) sends a crafted request to the vulnerable interface, overflowing a buffer and hijacking control flow. No credentials or user interaction are required, and successful exploitation yields arbitrary code execution as a privileged user on the underlying OS. No public exploit code has been identified at time of analysis.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.6% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 29, 2026

Unauthenticated remote code execution in HPE Networking Instant On firmware through 3.4.1.0 allows an attacker who can reach the device's affected network interface to exploit a buffer overflow and execute arbitrary code as a privileged user on the underlying host (CVSS 9.8, AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). No public exploit code and no confirmed active exploitation (CISA KEV) were identified at time of analysis, but exploitation requires only network reachability to the exposed interface, so internet-facing or unsegmented Instant On access points and switches carry the greatest exposure. HPE has addressed the flaw in firmware versions above 3.4.1.0.

RemediationAI

Upgrade Instant On devices to a firmware release above 3.4.1.0; the HPE advisory hpesbnw05150en_us (https://support.hpe.com/hpesc/public/docDisplay?docId=hpesbnw05150en_us&docLocale=en_US) identifies the fixed version, and the exact patched build should be taken from that bulletin rather than assumed. Until the upgrade is applied, reduce exposure by ensuring the vulnerable interface is not reachable from untrusted networks: block management/service ports at the WAN edge, place Instant On devices on a dedicated management VLAN segmented from user and guest traffic, and restrict administrative access to a jump host or VPN. Where remote cloud management is not essential, disabling the cloud/remote-management path removes a network-facing attack surface at the cost of losing remote configuration and telemetry; where it is essential, allow only the vendor's documented management endpoints. These compensating controls are exposure reductions, not fixes - the memory-safety flaw remains exploitable by anyone who reaches the interface, so patching should be prioritized for any device that is internet-facing or shares a segment with untrusted users. Monitor HPE's bulletin for updated patched versions and any interim mitigation guidance.

Affected VersionsENISA

Instant On 0.0.0.0 ≤3.4.1.0

Affected Packages

euvd instant_on no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

HPE Networking Instant On is a cloud-managed networking product line whose access points and switches run embedded firmware on a Linux-based host OS. The vulnerability is a memory-safety defect classified under the Buffer Overflow tag (no CWE identifier was supplied with the record), occurring in an unspecified network-facing interface - most likely a management or service daemon listening on the device. Because the overflow is reachable pre-authentication and without user interaction (PR:N/UI:N per the CVSS vector) and corrupts memory in a process running with elevated rights, successful exploitation yields arbitrary code execution at privileged level on the underlying operating system rather than merely crashing the service. The CPE entry cpe:2.3:a:hewlett_packard_enterprise_(hpe):instant_on:*:*:*:*:*:*:*:* carries a wildcard version, and EUVD-2026-89340 narrows the affected range to Instant On firmware from 0.0.0.0 through 3.4.1.0. The exact interface, port, and protocol are not specified in the available data and must be confirmed against HPE advisory hpesbnw05150en_us before any tailoring of network controls.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (hpe) PRIMARY 9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI 9.8 CRITICAL

Vendor confirms unauthenticated remote buffer overflow yielding privileged code execution, so AV:N/AC:L/PR:N/UI:N with full C/I/A impact on the affected host.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (hpe).

CVSS VectorVendor: hpe

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

DescriptionCVE.org

Buffer overflow vulnerability exists in the affected interface of HPE Networking Instant ON that could allow an unauthenticated remote attacker to run arbitrary code on the underlying host. Successful exploitation could allow an attacker to execute arbitrary code as a privileged user on the underlying operating system.

Executive ViewAI

Why It Matters

HPE Networking Instant On access points and switches running firmware through 3.4.1.0 contain a critical, unauthenticated remote code execution flaw that lets anyone who can reach the device's network interface run code with privileged access on the underlying host. Because no credentials or user interaction are required, any Instant On gear exposed to the internet or sitting on flat, unsegmented networks becomes a potential entry point into the corporate environment. Leadership should treat this as a network-perimeter risk: compromise of these devices could give an attacker a privileged foothold from which to move laterally into business systems, even though no public exploit or active exploitation has been observed to date.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: remove affected Instant On devices from internet exposure and place them behind firewall/VPN; segment them onto a dedicated management VLAN with strict ACLs so only trusted administrators can reach the affected interface; disable unused services and remote management; monitor device and upstream switch logs for anomalous or unexpected traffic. Where the vendor advisory references fixed firmware above 3.4.1.0, upgrading to that release is the primary remediation path once the exact version is confirmed.

Threat Intelligence Overview

EPSS Score
0.6%
Top 56% exploitable
Prevalence
Medium
HPE cloud-managed SMB networking line (APs/switches), common but not everywhere
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.6%
Patch available No
Active threat No
Deciding rule
CRITICAL severity
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
Yes
Human Impact
High
Technical Impact
Total

Priority Score

50
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +49
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

CVE-2026-76722 CRITICAL
9.8 Sep 29

Unauthenticated remote command execution is possible on HPE Networking Instant On access points running firmware version

CVE-2026-76725 CRITICAL
9.6 Sep 29

Authentication controls in the management protocol of HPE Networking Instant On access points (firmware ≤3.4.1.0) can be

CVE-2026-76724 CRITICAL
9.6 Sep 29

Unauthenticated command injection in the CLI of HPE Networking Instant On access points allows an attacker on the same a

CVE-2026-76723 CRITICAL
9.6 Sep 29

Unauthenticated attackers on the same Layer-2/wireless broadcast domain as an HPE Networking Instant On access point can

CVE-2026-76726 HIGH
8.1 Sep 29

An authentication bypass in the API endpoint of HPE Networking Instant ON (affected versions 0.0.0.0 through 3.4.1.0) al

CVE-2026-76728 HIGH
7.2 Sep 29

Server-side request forgery (SSRF) in the management API endpoint of HPE Networking Instant ON access points lets an aut

CVE-2026-76727 HIGH
7.2 Sep 29

Command injection in HPE Networking Instant ON firmware versions up to and including 3.4.1.0 allows an authenticated rem

CVE-2026-76729 MEDIUM
6.6 Sep 29

Memory corruption reachable through an unvalidated format string in the management API of HPE Networking Instant On acce

CVE-2026-76731 MEDIUM
6.5 Sep 29

Authentication bypass in the captive portal of HPE Networking Instant On (all versions up to and including 3.4.1.0) lets

CVE-2026-76730 MEDIUM
6.5 Sep 29

Authentication bypass in the PAPI control-plane protocol of HPE Networking Instant On access points running firmware 3.4

CVE-2026-76732 MEDIUM
6.4 Sep 29

Local privilege escalation in HPE Networking Instant On firmware 3.4.1.0 and earlier allows an attacker who already hold

CVE-2026-76733 MEDIUM
4.9 Sep 29

Denial of service in HPE Networking Instant On firmware version 3.4.1.0 and earlier lets a remote attacker who already h

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