CVE-2026-25802 is a Cross-Site Scripting (XSS) vulnerability classified under CWE-79, affecting the QuantumNous new-api product, specifically versions before 0.10.8-alpha.9. The vulnerability arises from improper neutralization of input during web page generation in the MarkdownRenderer.jsx component. This component processes outputs from a large language model (LLM) gateway and AI asset management system. When the model outputs items containing <script> tags, the component fails to sanitize or encode these inputs properly, allowing malicious scripts to be injected into the rendered web pages. This can lead to execution of arbitrary JavaScript in the context of the victim's browser session. The vulnerability requires low privileges (PR:L) and user interaction (UI:R) to exploit but does not impact confidentiality directly (C:N). However, it severely impacts integrity (I:H) by enabling script injection and has a low impact on availability (A:L). The vulnerability has a CVSS 3.1 score of 7.6, indicating high severity. No known exploits are currently reported in the wild. The issue was addressed in version 0.10.8-alpha.9 by implementing proper input sanitization or output encoding to neutralize potentially dangerous script tags in the model output. This vulnerability is particularly critical given the increasing reliance on AI-driven systems and LLM gateways, which may process untrusted or dynamically generated content. Attackers exploiting this flaw could perform actions such as session hijacking, defacement, or injecting malicious payloads to compromise user interactions with the system.

The impact of CVE-2026-25802 on organizations worldwide can be significant, especially for those deploying QuantumNous new-api in AI asset management or LLM gateway roles. Successful exploitation allows attackers to execute arbitrary scripts in users' browsers, potentially leading to session hijacking, unauthorized actions, or delivery of malware. This undermines the integrity of the system and user trust. While confidentiality is not directly compromised, the integrity breach can facilitate further attacks or data manipulation. The requirement for user interaction and low privileges lowers the barrier for exploitation, increasing risk in environments where users frequently interact with AI-generated content. The availability impact is limited but could occur if injected scripts disrupt normal operations. Organizations relying on AI systems for critical workflows or sensitive data management may face operational disruptions, reputational damage, and compliance issues if this vulnerability is exploited. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits after public disclosure.

To mitigate CVE-2026-25802, organizations should immediately upgrade QuantumNous new-api to version 0.10.8-alpha.9 or later, where the vulnerability is fixed. Beyond patching, implement strict input validation and output encoding in all components that render user or model-generated content, especially those handling HTML or markdown inputs. Employ Content Security Policies (CSP) to restrict the execution of unauthorized scripts and reduce the impact of potential XSS attacks. Conduct thorough code reviews and security testing focusing on injection flaws in components processing dynamic content. Educate users about the risks of interacting with untrusted AI-generated content and monitor logs for suspicious activities indicative of attempted XSS exploitation. Additionally, consider sandboxing or isolating AI output rendering environments to limit the scope of script execution. Regularly update and audit third-party dependencies to ensure no similar vulnerabilities exist. Finally, maintain an incident response plan tailored to web-based attacks to quickly contain and remediate any exploitation attempts.