What is the CVSS score of CVE-2026-73798?

CVE-2026-73798 has a CVSS 3.1 base score of 8.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H. EPSS exploitation probability: 0.3%.

How to fix or mitigate CVE-2026-73798?

Within 24 hours, inventory every HPE NonStop installation and confirm which run the DNS 9.2.3 Non Secure Version; restrict network access to the DNS listener with firewall or ACL rules so only trusted resolver clients and management subnets can reach it, and enable monitoring or alerting on DNS service health for those hosts. Within 7 days, engage HPE support to obtain a definitive remediation timeline and any available hotfix, test whether the secure DNS variant can be deployed as a replacement path, and validate that rate-limiting or filtering rules on the DNS listener do not degrade legitimate resolution traffic. Within 30 days, apply the vendor-released patch as soon as it is published (no fix version is identified at time of analysis), re-verify compensating access controls remain in force at every boundary, and document the residual exposure for audit and incident-response planning.

HPE NonStop DNS CVE-2026-73798

EUVD-2026-101006 HIGH

Misinterpretation of Input (CWE-115)

2026-10-14 hpe

GHSA-vcv9-4mjq-qpxh

Denial Of Service Hpe Nonstop Dns 9 2 3 Non Secure Version

8.2

CVSS 3.1 · Vendor: hpe

View

Attack ChainAIDerived

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

Access

Reach NonStop DNS service over network
Delivery

Send crafted malformed DNS message
Exploit

Trigger input misinterpretation in parser
Execution

Crash or hang resolver process
Impact

Denial of name-resolution service

Vulnerability Assessment

Weakness	CWE CWE-115 OWASP Top 10:2025 A05:2025 - Injection ASVS 5.0 V1 - Encoding and Sanitization Output interpretation safety
Exploitation Conditions	Exploitation requires network reachability to the HPE NonStop DNS 9.2.3 'Non Secure Version' service; per AV:N/AC:L/PR:N/UI:N it needs no authentication, no user interaction, and works against the service as exposed. The key limiting factor is deployment scope rather than configuration: only HPE NonStop systems running this specific DNS component are affected, and the 'Non Secure Version' qualifier in the product name suggests the hardened/secure variant may not be impacted - exposure also depends on whether the DNS listener is reachable from untrusted networks rather than restricted to an internal NonStop environment. The precise malformed-input trigger (CWE-115 misinterpretation of input) is not specified in the available data.
Impact	The input CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H) describes a remotely reachable, low-complexity, unauthenticated flaw whose primary consequence is high availability impact (A:H) with incidental low integrity impact (I:L) and no confidentiality impact - consistent with the Denial of Service classification and CWE-115 (Misinterpretation of Input), which points to a DNS message/input parsing defect. No EPSS probability, SSVC decision data, KEV listing, or POC reference was provided, so there is no public exploit identified at time of analysis and no evidence of active exploitation; the only reference is the HPE vendor advisory (hpesbns05148en_us). This means the 8.2 score is driven almost entirely by the theoretical network-reachable availability impact rather than by any observed exploitation signal. The practical risk is tempered by the extremely narrow deployment footprint of HPE NonStop DNS: the vulnerability is genuinely remote-unauthenticated per PR:N, but the affected product runs only on HPE NonStop fault-tolerant systems, so this is best treated as a vendor-driven patch-when-available item for the small population of NonStop operators rather than a broad-internet emergency. Note the scope is unchanged (S:U), so impact is confined to the vulnerable DNS service/host.
Exploit ScenarioDerived	A remote, unauthenticated attacker who can reach the HPE NonStop DNS service sends a crafted or malformed DNS query/response that the service misinterprets during parsing, causing the resolver process to crash or hang and denying name-resolution service to dependent applications. No user interaction or credentials are required (AV:N/PR:N/UI:N), but no public proof-of-concept exploit has been identified at time of analysis.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

No patch listed yet 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 14, 2026

Denial of service in HPE NonStop DNS 9.2.3 (Non Secure Version) lets an unauthenticated remote attacker disrupt the DNS service on affected NonStop systems by supplying crafted input that the service misinterprets. The CVSS 3.1 vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H (base 8.2) confirms network reachability, low attack complexity, no authentication and no user interaction, with a high availability impact, minor integrity impact and no confidentiality impact. Exposure is narrow - only HPE NonStop installations running this specific 'Non Secure Version' DNS component are affected, and reachability of the DNS listener determines real-world risk; no public exploit code identified at time of analysis and no confirmed active exploitation.

RemediationAI

Apply the fix referenced in HPE Security Bulletin hpesbns05148en_us (https://support.hpe.com/hpesc/public/docDisplay?docId=hpesbns05148en_us&docLocale=en_US); the exact patched version is not stated in the available data, so treat the bulletin as the authoritative source for the fixed NonStop DNS build rather than assuming a version number - patch status is not confirmed from the supplied intelligence. Where the DNS component cannot be updated immediately, reduce the attack surface by restricting the DNS listener to trusted networks with host firewall or ACL rules, accepting the trade-off that legitimate external or cross-zone resolvers will be unable to query it, and by removing open-recursion/forwarder functionality if it is not required, accepting that internal clients will lose recursive resolution. Enabling DNS response rate limiting (RRL) or upstream query throttling can blunt repeated malformed queries but will also drop legitimate traffic during a burst, so tune thresholds against production query volume. If a hardened/secure DNS variant of the NonStop component is supported in your environment, migrating to it is a viable compensating control given the 'Non Secure Version' designation, and process supervision or automatic restart of the DNS service can shorten outage windows at the cost of masking recurrence. Monitor the advisory for updated fix guidance before relying solely on mitigations.

Affected VersionsENISA

HPE NonStop DNS 9.2.3 Non Secure Version T0685L01^BAE and earlier

Affects your stack

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Technical ContextAI · show details

The root cause class is CWE-115 (Misinterpretation of Input), which in a DNS service context points to a parser that accepts a syntactically valid but semantically malformed message, record, or field and then takes an unintended code path - typically a length, type, or encoding assumption that breaks inside the name server's query/response handling. Because the flaw is invoked over the DNS protocol itself, the vector is AV:N/AC:L/PR:N/UI:N with no privileges or interaction required, and because impact is scored A:H with C:N, the endpoint of the misinterpretation is availability of the resolver/name service rather than data disclosure; the I:L component indicates a limited ability to alter state (for example a response or configuration value) as a side effect. The CPE cpe:2.3:a:hewlett_packard_enterprise:hpe_nonstop_dns_9.2.3_non_secure_version:*:*:*:*:*:*:*:* identifies the affected artifact as the 'Non Secure Version' of the DNS component shipped with HPE NonStop 9.2.3, which implies a separate hardened variant of the product exists and may not share the defect. The precise malformed-input trigger is not specified in the available data.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (hpe) PRIMARY 8.2 HIGH

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

vuln.today AI 8.2 HIGH

Network-reachable DNS parsing flaw needs no auth or interaction (AV:N/AC:L/PR:N/UI:N); impact is service crash (A:H) with incidental I:L and no confidentiality (C:N), scope unchanged.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/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

None

Integrity

Low

Availability

High

DescriptionCVE.org

A security vulnerability in HPE NonStop DNS 9.2.3 Non Secure Version could cause a Denial of Service.

Executive ViewAI

Why It Matters

HPE NonStop systems running the Non Secure Version of the DNS 9.2.3 component are exposed to a remotely reachable flaw that allows an unauthenticated attacker to disrupt DNS service availability on those hosts. Because the affected component is a non-secure build, environments relying on it may face unplanned DNS outages until HPE releases remediation, though exposure is limited to that specific configuration and reachability of the DNS listener. Leadership should treat this as an availability risk affecting a narrow but business-critical slice of the NonStop estate, and direct asset owners to confirm their exposure and apply interim network protections.

Business Impact: High

Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: restrict network reachability of the affected DNS listener to trusted clients and management subnets via firewall, ACL, or segmentation controls; enable rate-limiting and input filtering at the network boundary; monitor DNS service availability and alert on restart or degradation; evaluate migration off the DNS 9.2.3 Non Secure Version to the secure variant; coordinate with HPE support for hotfix availability and remediation timeline.

Threat Intelligence Overview

EPSS Score

0.3%

Top 76% exploitable

Prevalence

Rare

niche HPE NonStop fault-tolerant platform, tiny specialized install base

Data Quality

4 sources

Confidence: Medium

EUVD

NVD

CVE.org

EPSS

Vulnrichment

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 HIGH

CISA KEV No

Public POC No

EPSS 0.3%

Patch available No

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

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.