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HPE Instant On CVE-2026-76722

| EUVDEUVD-2026-89341 CRITICAL
Use of Externally-Controlled Format String (CWE-134)
2026-09-29 hpe GHSA-6rfv-6396-m883
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 AP interface
  2. Delivery
    Send request with malicious format specifiers
  3. Exploit
    Trigger uncontrolled format string parsing
  4. Execution
    Corrupt memory write primitive
  5. Impact
    Execute arbitrary commands on host or crash service

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Format string safety
Exploitation Conditions

Exploitation requires only network reachability to the affected interface of an HPE Networking Instant ON access point running firmware ≤3.4.1.0; per CVSS PR:N/UI:N/AC:L it is unauthenticated, needs no user interaction, and works against default configurations. The primary limiting factor is network exposure of the vulnerable AP interface - deployments where that management/service interface is not reachable from an attacker-controlled segment are not exposed. The exact vulnerable interface/service is not named in the advisory description, so network segmentation/filtering of the AP interface and confirming patched firmware are the key mitigations.

Impact

This is a genuine high-priority issue, not merely a high-CVSS-but-low-real-risk finding. The vendor-supplied CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, 9.8) describes the most dangerous class of network flaw: remote, unauthenticated, low-complexity, no user interaction, with full CIA impact leading to arbitrary command execution on the underlying host of HPE Networking Instant ON access points. The description confirms an uncontrolled format string reachable on an exposed AP interface, a well-understood and reliably weaponizable bug class. Signal comparison: EPSS is not provided in the input; KEV status is not listed (no evidence of confirmed active exploitation); and no public POC is referenced - so all exploitation-maturity signals are currently absent. However, absence of EPSS/KEV/POC does not lower the intrinsic risk here: the bug is vendor-confirmed (reported by HPE with an official advisory), a patch boundary is defined (≤3.4.1.0 affected), and format-string-to-RCE on unauthenticated network-facing embedded devices is historically attractive to attackers and botnets. No signals conflict with the CVSS assessment; description and vector are mutually consistent. Recommend treating as urgent for any exposed Instant ON deployment pending confirmation of the exact fixed version from the HPE advisory.

Exploit ScenarioDerived

An attacker who can reach the network-facing management/service interface of an HPE Networking Instant ON access point sends a crafted request containing attacker-controlled format specifiers to the vulnerable parser, corrupting memory to either crash the process (DoS) or redirect execution to run arbitrary commands as the host process. No authentication or user interaction is required. No public exploit code is referenced at time of analysis, but format-string-to-RCE is a reliably exploitable pattern on such devices.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
No patch listed yet 0.5% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 29, 2026

Unauthenticated remote command execution is possible on HPE Networking Instant On access points running firmware version 3.4.1.0 and earlier, due to uncontrolled format string handling in an exposed interface of the device. Per the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, base 9.8), an attacker who can reach that interface over the network needs no credentials and no user interaction, and successful exploitation can run arbitrary commands on the underlying host, causing denial of service or full compromise. No public exploit code has been identified at time of analysis and the issue is not listed as confirmed actively exploited (CISA KEV), but the low attack complexity and default-configuration reachability make it a genuine high-priority exposure for any Instant On AP whose vulnerable interface is accessible from an untrusted segment.

RemediationAI

Apply the fixed Instant On firmware release published in HPE security advisory hpesbnw05150en_us (https://support.hpe.com/hpesc/public/docDisplay?docId=hpesbnw05150en_us&docLocale=en_US); the advisory reference is provided without an explicit fixed version string in the available data, so confirm the exact patched firmware number from the HPE document rather than assuming any version above 3.4.1.0 is sufficient. Until upgraded, the highest-value control is removing network reachability to the affected AP interface: place Instant On APs on a dedicated management VLAN, block inbound access to AP management/service ports from user, guest, and internet-facing segments, and explicitly deny any NAT or firewall forwarding rule that publishes an AP interface externally. Restricting the AP's own wireless clients and guest networks from reaching the management plane also reduces the attack surface, at the cost of some administrative convenience for troubleshooting. Where the vulnerable service cannot be fully segmented, monitor AP and upstream switch logs for anomalous command execution or unexpected reboots and treat any AP that has been reachable from untrusted networks as potentially compromised, requiring a factory reset and re-provisioning after patching. Note that firmware downgrades and rollback to versions ≤3.4.1.0 reintroduce the vulnerability, so configuration backups taken before the fix should not be used to restore older firmware.

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

The root cause is an uncontrolled format string condition (the class described in CWE-134) in one of the network-facing interfaces of HPE Networking Instant On access points. Format string bugs arise when attacker-supplied data is passed as the format argument to a printf-family function rather than as a plain string argument; the attacker can then use conversion specifiers such as %n and %s to read from and write to arbitrary memory addresses, which typically escalates to control-flow hijacking and arbitrary command execution on the underlying host. Because the affected component processes input from the network before any authentication check, the vulnerable code path is reachable unauthenticated, and the CVSS scope is unchanged (S:U) with high confidentiality, integrity, and availability impact. The specific interface/service is not named in the vendor documentation, so defenders must treat the entire management and service surface of the AP as potentially affected. The CPE string cpe:2.3:a:hewlett_packard_enterprise_(hpe):instant_on:*:*:*:*:*:*:*:* does not version-qualify, so version scoping relies on the advisory data, which caps affected firmware at 3.4.1.0 (tracked in ENISA EUVD as EUVD-2026-89341).

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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

Unauthenticated network-reachable format string with no user interaction yields AV:N/AC:L/PR:N/UI:N, and RCE on the host gives full C:H/I:H/A:H within the same component (S:U).

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

Uncontrolled Format string vulnerabilities exist in the affected interface of HPE Networking Instant ON APs that could allow an unauthenticated remote attacker to run arbitrary commands on the underlying host. Successful exploitation could result in a Denial-of-service or potential remote code execution.

Executive ViewAI

Why It Matters

HPE Networking Instant On access points running firmware 3.4.1.0 and earlier contain an unauthenticated remote command execution flaw (CVE-2026-76722, CVSS 9.8) that allows anyone able to reach the device's exposed interface to run arbitrary commands without credentials or user interaction. Because these APs typically sit on the network edge in default configurations, a single reachable unit could serve as an entry point to the broader corporate network or be disabled outright, disrupting wireless connectivity for the business units that depend on it. No vendor-released patch has been identified and no public exploit code exists at time of analysis, but the low attack complexity means leadership should treat this as a near-term exposure requiring containment action rather than routine patching.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: isolate affected Instant On APs on a dedicated management VLAN, block access to the exposed interface from untrusted and guest networks at the firewall, disable non-essential remote management exposure, restrict administrative access to trusted management hosts, and enable logging and alerting on the APs and their upstream infrastructure to detect exploitation attempts. No public exploit code exists at time of analysis and the issue is not confirmed actively exploited (CISA KEV).

Threat Intelligence Overview

EPSS Score
0.5%
Top 57% exploitable
Prevalence
Medium
HPE Instant On is a common SMB-focused Wi-Fi AP line, not universal infrastructure
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 0.5%
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

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

CVE-2026-76721 CRITICAL
9.8 Sep 29

Unauthenticated remote code execution in HPE Networking Instant On firmware through 3.4.1.0 allows an attacker who can r

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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