CVE-2026-88742 in Bacularis
Summary
by MITRE • 09/15/2026
Bacularis 1.0.0 - 6.5.0 is vulnerable to Stored cross-site scripting (XSS) in the client address field.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability identified in Bacularis versions ranging from 1.0.0 through 6.5.0 represents a significant security flaw within the web-based management interface of this backup software suite. Specifically, the defect resides in the handling of the client address input field, which fails to adequately sanitize user-supplied data before rendering it back to the browser without proper encoding or validation. This oversight allows an attacker to inject malicious JavaScript code that is subsequently stored on the server-side database and served to other users upon subsequent requests. Because this is a Stored Cross-Site Scripting vulnerability, also known as Type 1 XSS, the impact extends beyond the initial injection point, affecting any user who views the compromised data within their web session.
From a technical perspective, the root cause lies in insufficient input validation and output encoding mechanisms during the processing of client address entries. When an administrator or authorized user enters a value into this field, the application accepts it without verifying that the content adheres to expected formats such as valid IP addresses or hostnames. Instead of rejecting malformed inputs or escaping special characters like angle brackets, quotes, and ampersands, the system persists these values directly into its backend storage. Consequently, when another user accesses the client list or details page where this address is displayed, the browser interprets the embedded script tags as executable code rather than plain text. This behavior violates fundamental web application security principles regarding data integrity and safe rendering practices.
The operational impact of this vulnerability is severe due to its persistent nature and potential for widespread exploitation. An attacker who gains access to a valid account within Bacularis can craft a payload that executes arbitrary JavaScript in the context of other users' sessions. This capability enables session hijacking, where the attacker steals authentication cookies or tokens to impersonate legitimate administrators. It also facilitates credential theft through phishing techniques embedded within the malicious script, as well as defacement of the user interface by altering DOM elements. In environments where Bacularis manages critical backup infrastructure, such compromise could lead to unauthorized modifications of backup schedules, deletion of restore points, or exfiltration of sensitive data protected by these backups. The persistence of the payload means that even if the initial attacker is removed from the system, the threat remains active for all future visitors until the malicious entry is manually purged from the database.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-79, which classifies improper neutralization of input during web page generation as a classic cross-site scripting flaw. Furthermore, in terms of tactical mapping within the MITRE ATT&CK framework, this exploit scenario corresponds to T1059 Command and Scripting Interpreter under Execution techniques, specifically when used for client-side script execution. It also relates to T1078 Valid Accounts if the attacker leverages stolen credentials obtained via the XSS payload to maintain persistent access. The lack of input validation reflects a broader pattern often seen in legacy or less rigorously audited enterprise applications where convenience is prioritized over security hardening during development cycles.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. For organizations currently running affected versions, the most effective short-term solution is to apply any available patches released by Bacularis vendors that specifically target this XSS flaw in version 6.5.0 or later releases if applicable. If patching is not immediately feasible, administrators should implement strict input validation rules at the application layer to reject non-standard characters in client address fields and enforce output encoding using context-aware methods such as HTML entity encoding for all dynamic content rendered in web pages. Additionally, deploying a Web Application Firewall can provide an additional layer of defense by filtering out known XSS payloads before they reach the vulnerable component. Long-term remediation requires adopting secure coding standards that mandate sanitization libraries and automated security testing during the software development lifecycle to prevent similar defects from being introduced into future updates.