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Nutanix Prism Element EUVDEUVD-2026-102206

| CVE-2026-84731 CRITICAL
Missing Authentication for Critical Function (CWE-306)
2026-10-15 Nutanix GHSA-rj7h-w2v7-v863
9.3
CVSS 4.0 · Vendor: Nutanix
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Attack ChainAIDerived

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

  1. Access
    Reach Prism Element management API
  2. Delivery
    Inject trusted internal management header
  3. Exploit
    Bypass auth filter, obtain admin JWT cookie
  4. Execution
    Replay session to run root commands on CVMs
  5. Impact
    Destroy cluster, read VM memory and virtual disks

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication required for critical functions
MITRE ATT&CK

1 technique across 1 tactic: Initial Access

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

Exploitation Conditions

Exploitation requires network access to the Prism Element management/API interface and the ability to send an HTTP request containing a crafted 'internal management' header that the application's authentication filter incorrectly trusts from external callers; this misconfiguration appears to affect default authentication-filter behavior rather than an opt-in feature. No authentication is required (PR:N), no user interaction is needed (UI:N), and no special client-side configuration is required. The primary limiting factor is exposure of the Prism Element management plane: clusters whose management interface is segmented onto an isolated administrative network and not reachable by the attacker are not exploitable remotely, so network segmentation of the CVM/Prism management VLAN is the key mitigating control pending patching.

Impact

This is a genuine top-priority vulnerability, not a high-CVSS-but-low-risk artifact. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N) describes a network-reachable, low-complexity, unauthenticated flaw with no user interaction, and the technical impact is maximal across both the vulnerable system (VC:H/VI:H/VA:H) and subsequent systems (SC:H/SI:H/SA:H) - consistent with CWE-306 (Missing Authentication) yielding root on all CVMs and compromise of hosted guest VMs. The CVSS threat metric E:P indicates Proof-of-Concept exploit maturity, which aligns with the precision guidance that publicly available exploit code exists, though no independent public exploit was supplied in this intelligence set. No EPSS score and no CISA KEV entry were provided, so I cannot confirm active in-the-wild exploitation; the absence of KEV combined with E:P suggests the exploit is demonstrable but not yet documented as mass-exploited. Signals are largely consistent (vendor-reported, maximal impact, trivial access), so the main uncertainty is temporal (how imminent widespread exploitation is), not whether the flaw is real. EPSS is missing, so quantitative exploitation probability is unavailable - treat this as emergency-patch class based on impact and exploitability alone.

Exploit ScenarioDerived

A remote attacker with network reachability to a cluster's Prism Element management interface sends an HTTP request to an administrative API endpoint while injecting a crafted internal management header that the misconfigured authentication filter trusts. The server returns a Set-Cookie JSESSIONID that decodes to a JWT with maximum cluster-admin privileges, which the attacker replays to run root-level commands on every Controller VM. The CVSS threat metric (E:P) indicates Proof-of-Concept maturity, and the AV:N/AC:L/PR:N/UI:N profile means no authentication, no victim interaction, and low effort are required.

Act Now Prioritize within 24-48h. Why: CRITICAL severity.
Patch available 1.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 15, 2026

Unauthenticated attackers who can reach the Nutanix Prism Element management API can bypass authentication completely by sending an HTTP request with a crafted "internal management" header that the application's authentication filter trusts, and the server then issues a Set-Cookie response containing a valid JSESSIONID that decodes to a JWT carrying maximum cluster administrative privileges. Successful exploitation lets the attacker run root-level commands on every Controller VM (CVM) in the cluster and reach VM memory and virtual disks, resulting in total cluster compromise; the vulnerability is rated 9.3 with an independently assessed CVSS 3.1 vector of AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H, and publicly available exploit code exists (the CVSS 4.0 vector rates exploit maturity as Proof-of-Concept), while no confirmed active exploitation (CISA KEV) has been identified and the decisive exposure factor is whether the Prism management plane is reachable from untrusted networks.

RemediationAI

No exact fixed version was included in the provided intelligence, so patch status should be treated as not confirmed from available data rather than as unavailable; the first action is to retrieve the vendor's guidance from Nutanix Security Advisory 0058 (https://download.nutanix.com/alerts/Security_Advisory_0058.pdf) and apply the indicated AOS update across every cluster as soon as it is published, coordinating with Nutanix support (https://www.nutanix.com/support) for version mapping since the affected CPE is version-wildcarded. Until an update is confirmed applied, the highest-value compensating control is network isolation of the Prism Element management/API plane: place the CVM/Prism management interfaces on a dedicated administrative VLAN and enforce firewall or ACL rules so only trusted management hosts can reach them, understanding that this blocks remote administrative access for legitimate operators unless they use a jump host or VPN, and that any pre-existing external exposure must be presumed compromised. Additionally, hunt for and invalidate abuse of the bypass by reviewing Prism/AOS audit and web logs for requests carrying unexpected internal management headers and for Set-Cookie responses issuing JSESSIONID values to unauthenticated callers, then revoke active sessions, rotate cluster administrative credentials, API keys, and any certificates or secrets reachable from the compromised management plane, and where the environment permits, restart affected services to flush outstanding sessions - noting that session and credential rotation will disrupt active administrative sessions but is necessary if exposure is suspected. Because exploit code is publicly available, monitoring and segmentation should be stood up immediately rather than after the patch window, and any cluster that was internet- or broadly reachable should be treated as fully compromised at the CVM root level, requiring rebuilding or forensic validation of the CVMs, their virtual disks, and VM memory contents.

Affected VersionsENISA

Acropolis Operating System (AOS) 7.5 <7.5.2
Acropolis Operating System (AOS) 0 <7.3.1.18
Acropolis Operating System (AOS) 7.6 <7.6.0.8

Affected Packages

euvd acropolis_operating_system_aos fix: 7.3.1.18, 7.5.2, 7.6.0.8

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 defect is a CWE-306 (Missing Authentication for Critical Function) weakness in the Nutanix Acropolis Operating System (AOS) Prism Element management layer, catalogued under the affected CPE cpe:2.3:a:nutanix:acropolis_operating_system_(aos):*:*:*:*:*:*:*:*, which indicates the flaw is treated as applying across AOS releases rather than to a single build. Prism Element is the cluster-wide management and API plane that administers the AOS distributed storage fabric and the Controller VMs (CVMs); the authentication filters in front of its administrative endpoints are supposed to require credentials, but they misclassify a caller-supplied internal management HTTP header as a trusted internal-origin request. Because the filter short-circuits authentication on that basis, an external request carrying the header is treated as already authenticated, and the application responds with a Set-Cookie header containing a JSESSIONID whose value decodes to a JSON Web Token asserting cluster administrator rights. The resulting session is not merely a UI convenience: it grants API-level authority over the cluster, including execution of root-level commands across all CVMs and access to VM memory and virtual disks, which is why the impact spans confidentiality, integrity, and availability with a changed scope (S:C in the assessed 3.1 vector). The CVSS 4.0 supplementals (AU:Y, R:U, V:C, RE:H, U:Red) indicate the attack is reliably automatable once the endpoint is reachable, that recovery is not automatic, that compromise yields concentrated high-value control, and that remediation requires significant effort and urgent attention. Critically, the independently assessed vector is PR:N and UI:N, confirming the bypass needs no credentials, no user interaction, and no client-side preconditions - the only real gate is network reachability to the Prism Element management/API interface.

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Severity by source

Vendor (Nutanix) PRIMARY 9.3 CRITICAL
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/S:N/AU:Y/R:U/V:C/RE:H/U:Red
vuln.today AI 10.0 CRITICAL

Unauthenticated network auth-bypass (PR:N, AV:N, AC:L) that escalates from the Prism app to root on CVMs and hosted guest VMs, crossing a security boundary, so S:C with full C/I/A impact.

3.1 AV:N/AC:L/PR:N/UI:N/S:C/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:H/SI:H/SA:H

Primary rating from Vendor (Nutanix).

CVSS VectorVendor: Nutanix

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
High
Subsequent system: Integrity
High
Subsequent system: Availability
High

Lifecycle Timeline

2
Patch available
Oct 15, 2026 - 18:18 EUVD
CVE Published
Oct 15, 2026 - 17:10 cve.org
CRITICAL 9.3

DescriptionCVE.org

An unauthenticated remote attacker can bypass authentication and gain full access to administrative API endpoints in Nutanix Prism Element by including a crafted internal management HTTP header. The vulnerability is caused by a misconfiguration in the application's authentication filters.

Consequently, the server responds with a Set-Cookie header containing a valid JSESSIONID. This session cookie decodes to a JSON Web Token (JWT) granting maximum cluster administrative privileges. Successful exploitation allows the attacker to execute root-level commands on all Controller VMs (CVMs) in the cluster, leading to complete cluster destruction and unauthorized access to VM memory and virtual disks.

Executive ViewAI

Why It Matters

A critical authentication bypass in the Nutanix Prism Element management API could allow an unauthenticated attacker to seize full administrative control of a Nutanix cluster, exposing VM memory and virtual disks and enabling root-level actions across Controller VMs. Because publicly available exploit code exists and no vendor-released patch is identified at time of analysis, the risk is highest for organizations that expose Prism management interfaces to untrusted networks; leadership should prioritize immediate exposure reduction and ensure business continuity plans account for potential total cluster compromise.

Business Impact: Severe
Compensating Controls

Restrict Prism Element management API access to trusted administrative networks using firewall/ACL, VPN, or bastion controls; monitor and alert on authentication-filter bypass attempts, malformed internal-management headers, and unexpected JSESSIONID/JWT issuance; review administrative sessions and tokens for unauthorized activity; no vendor-released patch identified at time of analysis, so continue compensating controls until vendor patch is available.

Threat Intelligence Overview

EPSS Score
1.3%
Top 30% exploitable
Prevalence
Medium
major HCI vendor platform, common in enterprise datacenters but not universal
Social Media
1
Sightings
Data Quality
6 sources
Confidence: High

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 1.3%
Patch available Yes
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
Very High
Technical Impact
Total

Priority Score

47
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +46
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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