CVE-2026-76303 in SOAR
Summary
by MITRE • 10/22/2026
In Splunk SOAR versions below 8.7.0, a user that holds a role with the install_apps capability could store attacker-controlled content that Splunk SOAR displays in app documentation by installing an app. If another user who holds a role with permission to view apps opens the app documentation, Splunk SOAR could run that content in the browser of the user who opened the app documentation. With this access, the first user could access data and make changes that the user who opened the app documentation could make. The vulnerability is possible because Splunk SOAR does not sanitize app documentation content before it displays that content. The vulnerability requires the attacker to phish the affected user by tricking them into initiating a request within their browser. The user that holds a role with the install_apps capability should not be able to exploit the vulnerability at will. For more information see Manage roles and permissions in Splunk SOAR (On-premises) (https://help.splunk.com/en/splunk-soar/soar-on-premises/administer-soar-on-premises/7.1.0/manage-your-splunk-soar-on-premises-users-and-accounts/manage-roles-and-permissions-in-splunk-soar-on-premises) and Add and configure apps and assets to provide actions in Splunk SOAR (On-premises) (https://help.splunk.com/en/splunk-soar/soar-on-premises/administer-soar-on-premises/8.6.0/manage-your-splunk-soar-on-premises-apps-and-assets/add-and-configure-apps-and-assets-to-provide-actions-in-splunk-soar-on-premises) in the Splunk documentation.
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Analysis
by VulDB Data Team • 10/22/2026
The vulnerability identified in Splunk SOAR versions prior to 8.7.0 represents a critical security flaw rooted in insufficient input validation and output encoding, specifically within the application's documentation rendering engine. This issue allows for Cross-Site Scripting attacks where malicious actors can inject executable scripts into app documentation fields that are subsequently displayed to other users without proper sanitization. The core technical failure lies in the system's inability to distinguish between safe text content and potentially harmful script code when processing user-supplied data during the installation of custom applications. When an application is installed, any content entered into its documentation section is stored as-is by the backend database. Later, when another user with appropriate permissions views this app documentation, the browser interprets the stored content not merely as static text but as active executable code, leading to the execution of attacker-controlled JavaScript within the context of the victim's session.
This vulnerability exploits a classic Stored Cross-Site Scripting pattern where the malicious payload is persisted on the server and delivered to victims via normal web page requests. The operational impact is severe because it enables privilege escalation through social engineering rather than direct technical exploitation of authentication mechanisms. An attacker who possesses or compromises an account with the install_apps capability can craft a seemingly legitimate application containing embedded malicious scripts in its documentation field. By distributing this application within the organization, the attacker relies on a second user, typically one with higher privileges such as those capable of viewing apps and accessing sensitive data, to open the app's documentation page. Once that privileged user loads the page, their browser executes the injected script, granting the attacker full control over the victim's session context. This allows the attacker to perform actions indistinguishable from those performed by the legitimate user, including reading confidential security orchestration artifacts, modifying playbooks, accessing connected assets, and potentially exfiltrating sensitive data or disrupting automated response workflows.
From a classification perspective, this vulnerability aligns with CWE-79, which describes Improper Neutralization of Input During Web Page Generation known as Cross-site Scripting. The attack vector corresponds to ATT&CK technique T1059, Command and Scripting Interpreter, specifically through the use of browser-based scripting languages like JavaScript. Furthermore, it relates to CWE-643, Improper Mitigation for Pre-Attack Techniques, as the application fails to implement adequate safeguards against pre-existing malicious inputs that are later rendered in a security-sensitive context. The requirement for social engineering, such as phishing or tricking users into installing specific apps, places this within the realm of T1589, Gather Victim Identity Information, and potentially T1078, Valid Accounts if the attacker has compromised low-privilege credentials to install the app.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary defense is upgrading Splunk SOAR to version 8.7.0 or later, where this specific sanitization flaw in the documentation renderer has been addressed by implementing strict output encoding and context-aware escaping mechanisms that prevent script execution when rendering user-supplied content. In environments where immediate patching is not feasible, administrators should enforce strict role-based access control policies to limit the install_apps capability exclusively to trusted security operations personnel who have undergone rigorous verification processes. Additionally, organizations should implement Content Security Policy headers within their Splunk SOAR deployment to restrict inline script execution and define allowed sources for external resources, thereby mitigating the impact of any successfully injected scripts even if they bypass other controls. Regular auditing of installed applications and documentation content can also help detect anomalous entries that may indicate an ongoing exploitation attempt.