CVE-2026-108498 in BSK PDF Manager Plugin
Summary
by MITRE • 10/15/2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in bannersky BSK PDF Manager bsk-pdf-manager allows Stored XSS.This issue affects BSK PDF Manager: from n/a through 3.8.1.
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Analysis
by VulDB Data Team • 10/15/2026
The identified security flaw represents a classic instance of Improper Neutralization of Input During Web Page Generation, commonly known as Cross-Site Scripting or XSS. Specifically, this vulnerability manifests as a Stored XSS within the BSK PDF Manager application, version 3.8.1 and earlier versions in its affected range. Unlike reflected XSS attacks where malicious scripts are executed immediately upon user interaction with a crafted link, stored vulnerabilities persist on the target server. In this context, an attacker can inject malicious client-side script code into input fields or data structures that are subsequently saved by the application. When other users access pages containing this tainted data, their browsers execute the embedded scripts in the security context of the vulnerable web application. This persistence mechanism significantly amplifies the potential impact compared to non-persistent variants because a single successful injection can compromise multiple victims without requiring further interaction from the attacker beyond the initial payload submission.
From a technical perspective, the root cause lies in insufficient validation and sanitization of user-supplied input before it is rendered by the web application's backend or frontend logic. The BSK PDF Manager likely fails to properly escape special characters such as angle brackets, quotes, and ampersands when processing data intended for display within HTML documents. This allows an attacker to inject JavaScript code that runs in the context of the victim’s session. Because the payload is stored on the server, it becomes part of the dynamic content served to legitimate users who view PDF management interfaces or related pages. The vulnerability aligns with CWE-79, which categorizes improper neutralization of input during web page generation as a critical weakness leading to cross-site scripting attacks. This classification underscores the failure in implementing robust output encoding strategies that are essential for preventing script injection across various contexts within HTML documents.
The operational impact of this stored XSS vulnerability is severe and multifaceted. Once executed, the malicious scripts can perform actions on behalf of the victim user with their authenticated privileges. Attackers may steal session cookies or authentication tokens, enabling them to hijack active sessions and impersonate legitimate users without needing credentials. This capability facilitates unauthorized access to sensitive PDF documents managed by the application, potentially leading to data exfiltration, modification, or deletion depending on the permissions associated with the compromised account. Furthermore, attackers can manipulate the user interface through DOM manipulation techniques, redirecting victims to phishing sites designed to harvest additional credentials or install malware via drive-by downloads. The persistent nature of this flaw means that remediation is not sufficient; existing malicious payloads must also be purged from the database to prevent ongoing compromise until a patch is deployed and applied by all users.
In terms of threat modeling, this vulnerability maps directly to several tactics within the MITRE ATT&CK framework. It supports techniques such as Collection via Browser Capture or Screen Recording if scripts are designed to capture user input or screen content. More commonly, it facilitates Credential Access through Harvesting Credentials from a Browser by stealing cookies and local storage data. Additionally, it enables Persistence if attackers inject code that re-injects itself upon page load or modifies settings to maintain access. The attack vector is typically classified as Network-based with High complexity for the initial injection but Low complexity for subsequent exploitation since any user viewing the affected content triggers execution automatically. This makes social engineering less critical than in reflected XSS, though it remains relevant if attackers need to trick users into submitting specific malicious data initially.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary technical fix involves implementing strict input validation on all entry points where user data is accepted by the BSK PDF Manager application. This includes enforcing allowlists for expected character sets, lengths, and formats rather than relying solely on blocklists of dangerous characters. More critically, output encoding must be applied consistently across all contexts in which data is rendered, including HTML body content, attributes, JavaScript variables, and CSS properties. Utilizing modern web frameworks that automatically escape outputs by default can significantly reduce the risk of such oversights. For existing deployments, administrators should immediately review database records for suspicious script tags or encoded payloads and remove them to stop ongoing attacks while awaiting an official patch from the vendor.
Beyond immediate fixes, organizations should adopt a defense-in-depth approach to mitigate risks associated with stored XSS vulnerabilities even if patches are delayed. Implementing Content Security Policy headers can restrict the sources from which scripts are allowed to execute, thereby neutralizing many injected payloads that attempt to load external resources or run inline code. Additionally, deploying Web Application Firewalls configured with rulesets capable of detecting and blocking common XSS patterns in HTTP requests provides an additional layer of protection. Regular security assessments, including both automated static analysis tools focused on input handling logic and manual penetration testing by qualified professionals, are essential for identifying similar flaws before they can be exploited. Ensuring that development teams adhere to secure coding standards such as OWASP Top Ten guidelines will further reduce the likelihood of recurrence in future versions or related software components within the enterprise environment.