EUVD-2026-101815
GHSA-9rwj-hh6p-x6gp
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessReach TELSERV over network
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DeliverySend oversized crafted Telnet input
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ExploitOverflow stack buffer (CWE-121)
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ExecutionCorrupt service memory
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ImpactCrash TELSERV, deny service
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Stack buffer bounds checking
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | Requires network access to a host running HPE NonStop TELSERV (the NonStop Telnet server) with the service listening and reachable by the attacker; per CVSS PR:N/UI:N no authentication or user interaction is needed, so any party able to open a TELSERV session can attempt the overflow. Limiting factors: exploitation is confined to systems that actually run and expose TELSERV (a NonStop-specific component), impact is restricted to denial of service of that service rather than code execution or data disclosure, and only versions T9553L01^BAJ and earlier are affected - upgrading past that level removes the condition. |
| Impact | The input CVSS of 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) describes a network-reachable, low-complexity, unauthenticated flaw whose sole impact is availability (A:H) - consistent with the description's stack-based buffer overflow (CWE-121) leading only to memory corruption and DoS. No EPSS score, no CISA KEV listing, and no public POC were provided, so all three real-world exploitation signals are absent or neutral. There is no SSVC decision data supplied. Taken together, this reads as a genuinely remote-triggerable denial-of-service condition but NOT a code-execution or data-breach risk as scored; the vendor explicitly characterizes the outcome as DoS, and the CVSS vector agrees (C:N/I:N). The practical priority is tempered by the narrow blast radius (availability only) and the niche NonStop platform. Note a latent uncertainty worth verifying with HPE: stack-based buffer overflows CAN sometimes escalate to code execution, yet both the description and the vector restrict impact to availability - if HPE later confirms memory corruption is controllable, the I/C metrics and severity could rise. Treat as a moderate-priority patch for NonStop operators exposing TELSERV, lower priority elsewhere. |
| Exploit ScenarioDerived | A remote attacker with network reachability to a NonStop system's TELSERV (Telnet) service sends a crafted oversized input that overflows a stack buffer, corrupting memory and crashing or hanging the service, denying Telnet access to legitimate users. No authentication or user interaction is required per the CVSS vector. No public exploit code was identified at the time of analysis. |
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Alert meAnalysisAIv1 – Oct 15, 2026
Stack-based buffer overflow in HPE NonStop TELSERV versions T9553L01^BAJ and earlier allows remote, unauthenticated attackers to corrupt memory and crash the service, causing a denial of service. The flaw is network-reachable with low complexity and requires no authentication or user interaction per the CVSS vector (PR:N/UI:N), so any party able to open a TELSERV session can attempt the overflow. No public exploit identified at time of analysis, and the impact is limited to availability - no code execution or data disclosure is described.
RemediationAI
Upgrade HPE NonStop TELSERV beyond version T9553L01^BAJ; the vendor advisory (https://support.hpe.com/hpesc/public/docDisplay?docId=hpesbns05148en_us&docLocale=en_US) should be consulted for the exact patched version, which is not specified in the available data. If an immediate upgrade is not possible, restrict network access to TELSERV to trusted management networks only by applying firewall rules or NonStop IP filter policies that block untrusted sources from reaching the service port; this compensating control reduces exposure but may disrupt legitimate remote Telnet administration and does not eliminate the flaw. Disabling TELSERV entirely if it is not required eliminates the attack surface but removes Telnet-based management capabilities. Monitor for unexpected TELSERV process crashes as a potential sign of exploitation attempts.
Affected VersionsENISA
Affects your stack
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Technical ContextAI · show details
CWE-121 (Stack-based Buffer Overflow) in HPE NonStop TELSERV, the Telnet server component of the HPE NonStop operating system. The vulnerability arises from insufficient bounds checking when processing network input - likely during Telnet option negotiation or command parsing - allowing an attacker to write beyond a fixed-size stack buffer and corrupt memory. The affected CPE is cpe:2.3:a:hewlett_packard_enterprise:hpe_nonstop_telserv:*:*:*:*:*:*:*:* and the affected version range is T9553L01^BAJ and earlier. Successful exploitation results in memory corruption that can crash the TELSERV process, causing a denial of service; the CVSS impact subscore (A:H, C:N, I:N) confirms availability is the only affected security property.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
TELSERV is a network Telnet service reachable without auth or interaction (AV:N/AC:L/PR:N/UI:N); description limits impact to DoS so C:N/I:N/A:H.
Primary rating from Vendor (hpe).
CVSS VectorVendor: hpe
DescriptionCVE.org
A stack-based buffer overflow vulnerability in HPE NonStop TELSERV can cause memory corruption that may result in DoS.
Executive ViewAI
HPE NonStop TELSERV versions T9553L01^BAJ and earlier are affected by a remotely reachable, unauthenticated denial-of-service vulnerability that can crash the service and disrupt availability. Because no vendor patch is currently available and exploitation requires only network access to TELSERV, leadership should prioritize temporary network restrictions and monitoring while planning remediation. The impact is limited to availability, but downtime in NonStop environments can affect transaction processing and other critical business services.
Restrict network access to TELSERV to trusted hosts and networks, disable TELSERV where not operationally required, segment affected NonStop systems, monitor for crashes and abnormal session activity, and apply vendor-provided mitigations when available.
Threat Intelligence Overview
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.
What every action level means
SSVC AssessmentENISA
Priority Score
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.
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
Exploit-DB