CVE-2026-76454 in License On-Prem
Summary
by MITRE • 10/07/2026
A vulnerability in the Cisco Smart Licensing Utility API of Cisco License On-Prem, formerly Cisco Smart Software Manager On-Prem (SSM On-Prem), could allow an unauthenticated, remote attacker to write arbitrary files to the system or cause a DoS condition on an affected application.
This vulnerability is due to improper input validation and a lack of authentication in the management API. An attacker could exploit this vulnerability by sending a crafted request to the affected API. A successful exploit could allow the attacker to modify system files or cause a DoS condition.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 10/07/2026
The identified security flaw resides within the application programming interface (API) of the Cisco Smart Licensing Utility, which is part of the Cisco License On-Prem solution previously known as Cisco Smart Software Manager On-Prem. This component serves as a critical infrastructure element for organizations managing software licenses locally, facilitating communication between on-premises systems and Cisco’s licensing servers. The vulnerability stems from fundamental design oversights in how the API handles incoming requests, specifically regarding input validation mechanisms and authentication protocols. Because the affected endpoints do not enforce strict access controls or adequately sanitize user-supplied data, they present a significant attack surface for malicious actors operating over a network connection without requiring prior credentials to initiate an exploit sequence.
From a technical perspective, the core issue is classified as improper input validation combined with broken access control. The API fails to verify that incoming requests originate from authorized entities and does not sufficiently check the structure or content of data provided by clients. This deficiency allows an unauthenticated remote attacker to craft specific HTTP requests containing malicious payloads designed to interact directly with underlying file system operations or application logic. By exploiting these weaknesses, an adversary can manipulate internal processes in ways intended only for legitimate administrative users, effectively bypassing security boundaries that should prevent such interactions.
The operational impact of this vulnerability is severe and multifaceted. The primary risk involves arbitrary file write capabilities, which means a successful exploit could allow the attacker to create, modify, or overwrite files on the affected system with arbitrary content. This capability can lead to full system compromise if critical configuration files are altered, malicious scripts are injected for persistence, or sensitive data is exfiltrated through modified log files. Additionally, the vulnerability enables denial of service conditions against the application itself. By sending crafted requests that consume excessive resources or trigger unhandled exceptions within the API processing logic, an attacker can disrupt the availability of the licensing utility, thereby preventing legitimate users from managing their software licenses and potentially causing broader operational disruptions for dependent systems relying on this infrastructure.
In terms of industry standard classifications, this vulnerability aligns with CWE-284 Improper Access Control due to the lack of authentication requirements for sensitive API endpoints. It also relates closely to CWE-94 Improper Control of Generation of Code (Code Injection) or CWE-73 External Control of File Name or Path if the arbitrary file write is utilized to inject executable code or manipulate path traversal mechanisms. From a tactical standpoint, this behavior corresponds to MITRE ATT&CK techniques such as T1059 Command and Scripting Interpreter for executing commands via injected files, T1222 File and Directory Permissions Modification for altering system state, and potentially T1496 Resource Hijacking if the denial of service aspect is leveraged to consume computational resources.
Mitigation strategies must focus on immediate remediation through vendor-provided updates as well as defensive network configurations until patches are applied. Organizations should prioritize applying the latest security advisories released by Cisco for their specific version of License On-Prem or Smart Software Manager On-Prem, which address these input validation and authentication gaps. In environments where patching is not immediately feasible, implementing strict firewall rules to restrict access to the affected API endpoints solely from trusted management subnets can significantly reduce exposure. Additionally, deploying web application firewalls with rulesets designed to detect anomalous HTTP requests or unauthorized API calls may help block exploitation attempts by identifying patterns associated with arbitrary file writes and denial of service attacks targeting this specific utility.