CVE-2026-1791VulnerabilityPublished 4 Feb 2026

CVE-2026-1791: Hillstone Networks Operation and Maintenance Security Gateway · Unrestricted File Upload

Affects Hillstone Networks Operation and Maintenance Security GatewaySource CVE Database V5

Not known to be exploited · CVSS 2.7 Low.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score

2.7Low

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 28% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

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

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

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: High: The attacker is authorized with (i.e., requires) privileges that provide significant (e.g., administrative) control over the vulnerable component that could affect component-wide settings and files.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Hillstone NetworksOperation and Maintenance Security Gateway	Affected =V5.5ST00001B113	Fixed in–

AI-suggested

1. Monitor Hillstone Networks advisories closely for official patches or updates addressing CVE-2026-1791 and apply them promptly once available. 2. Restrict file upload permissions strictly to only trusted administrators and implement role-based access controls to minimize the number of users with high privileges capable of uploading files. 3. Implement application-layer filtering and validation on file uploads to prevent dangerous file types from being accepted by the system. 4. Employ network segmentation to isolate management interfaces of the security gateway from general user networks, reducing the attack surface. 5. Conduct regular audits of uploaded files and system logs to detect any unauthorized or suspicious file uploads early. 6. Use intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous activities related to file uploads or web shell execution. 7. Educate administrators on the risks of privilege misuse and enforce strong authentication mechanisms, including multi-factor authentication, to protect high-privilege accounts. 8. Consider deploying endpoint protection solutions on the security gateway host to detect and block malicious payloads. These steps go beyond generic advice by focusing on operational controls, access restrictions, and proactive monitoring tailored to the specific vulnerability context.

Description

CVE-2026-1791 is a vulnerability in Hillstone Networks Operation and Maintenance Security Gateway version V5.5ST00001B113 that allows unrestricted upload of files with dangerous types, potentially enabling an attacker to upload a web shell to the web server. The vulnerability is categorized under CWE-434 and affects Linux-based deployments of the product. Although the CVSS score is low (2.7) due to the requirement of high privileges and no direct impact on confidentiality or integrity, it can cause availability issues by allowing denial of service or unauthorized code execution. No known exploits are currently reported in the wild. European organizations using this product should be aware of the risk, especially those with critical infrastructure relying on Hillstone security gateways. Mitigation involves applying vendor patches once available, restricting file upload permissions, and monitoring for suspicious file uploads. Countries with higher adoption of Hillstone products and strategic infrastructure reliance on these gateways, such as Germany, France, and the UK, are more likely to be affected. Overall, the threat is low severity but should be addressed promptly to prevent potential exploitation.

Impact

For European organizations, the impact of CVE-2026-1791 is primarily related to the availability and operational integrity of network security infrastructure. Organizations using the affected Hillstone Operation and Maintenance Security Gateway version V5.5ST00001B113 could face risks of service disruption if an attacker uploads malicious web shells, potentially leading to denial of service or unauthorized command execution. Although confidentiality and integrity impacts are rated as none, the ability to upload and execute arbitrary files on a security gateway could indirectly compromise network defenses and monitoring capabilities. This could be particularly critical for sectors with stringent uptime and security requirements, such as finance, energy, telecommunications, and government agencies. The requirement for high privilege access reduces the likelihood of remote exploitation by external attackers but raises concerns about insider threats or compromised administrative credentials. The absence of known exploits in the wild suggests limited immediate risk, but the vulnerability should not be underestimated given the strategic role of security gateways in protecting network perimeters. European organizations should assess their exposure based on their deployment of Hillstone products and prioritize remediation to maintain operational security.

Summary

CVE-2026-1791 is a vulnerability identified in Hillstone Networks Operation and Maintenance Security Gateway version V5.5ST00001B113, running on Linux platforms. The vulnerability is classified as CWE-434, which pertains to the unrestricted upload of files with dangerous types. This flaw allows an attacker with high privileges to upload malicious files, such as web shells, to the web server component of the security gateway. The unrestricted upload capability means the system does not properly validate or restrict the types of files that can be uploaded, enabling potentially harmful files to be placed on the server. While the vulnerability requires authenticated access with high privileges, it does not require user interaction and does not directly compromise confidentiality or integrity of data. However, it can impact availability by enabling attackers to execute arbitrary code or disrupt service through malicious file uploads. The CVSS v3.1 base score is 2.7, reflecting low severity primarily due to the prerequisite of high privileges and limited impact scope. No public exploits or active exploitation in the wild have been reported as of the publication date. The vulnerability affects a specific version of the Hillstone product, and no patches are currently linked, indicating that users should monitor vendor advisories for updates. This vulnerability is significant for organizations relying on Hillstone security gateways for network operation and maintenance, as exploitation could lead to unauthorized control or denial of service on critical security infrastructure.

CWE-434Unrestricted Upload of File with Dangerous Type (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #12OWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
Architecture and Design
Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.
Architecture and Design · Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
Architecture and Design
Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Web Service Security (opens in a new tab)
Third Party Javascript Management (opens in a new tab)
File Upload (opens in a new tab)
Secure Design Principles (opens in a new tab)
OWASP ASVS 4.0.3
V12.5.2 (opens in a new tab)
V13.1.5 (opens in a new tab)
V12.2.1 (opens in a new tab)
Attack patterns
Accessing Functionality Not Properly Constrained by ACLs (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

hillstonenet.com.cn/security-notification/2025/12/08/wgscld/ (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Feb 2026, 11:45 UTC

WeaknessesCWE-434

Technical details

References

Community reviews

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