CVE-2025-48954 Scanner

Discourse is a popular open-source platform used for creating online forums and communities. It is adopted by organizations and individuals to facilitate discussions and engagement among users. Its social login functionality, which allows users to authenticate via third-party services, is a common feature employed to enhance user experience. Discourse supports various forms of user interaction, including messaging, notifications, and customizable features, making it a versatile tool for community management. It is commonly used by academic institutions, businesses, non-profit organizations, and enthusiast groups to build and manage user-friendly forums. The platform's adoption spans across different sectors due to its flexible configuration capabilities and active development community.

The Cross-Site Scripting (XSS) vulnerability allows attackers to inject malicious scripts into web pages viewed by other users. This specific vulnerability in Discourse arises from inadequate content security policy enforcement when handling OAuth/social login failures. Attackers can exploit this to execute arbitrary code in the context of a user's browser session. XSS vulnerabilities are critical as they can lead to unauthorized actions by unsuspecting users on a site they trust. Over time, persistent XSS vulnerabilities can be used to steal sensitive information, execute actions on behalf of the user, or compromise user accounts. Addressing such vulnerabilities is crucial for maintaining the security and trustworthiness of a platform.

The technical details of the vulnerability include flaws in the OAuth/social login mechanism where redirects are not properly sanitized. Attackers can manipulate the provider parameter to reflect malicious payloads through requests to the application. In the vulnerable versions of Discourse, attackers can use crafted requests to bypass existing security filters. Parameters susceptible to exploitation include redirect_payload and basic_xss, which can lead to the execution of malicious content or redirects. The absence of appropriate security headers further exacerbates the risk, allowing for robust penetration through manipulated content. The vulnerability exposes endpoints that fail to correctly handle exceptional states during login attempts.

If exploited, this vulnerability could allow malicious scripts to be executed on unsuspecting users' browsers, leading to potential data theft or injection of further malicious content. Users might unknowingly act on behalf of an attacker or become victims of further malicious exploitation. The implications extend to compromised sessions, unauthorized actions, and potential data breaches for organizations. Persistent vulnerabilities may also weaken the security posture and erode the trust of the user community on the platform. Administrators are at risk of dealing with increased security incidents and potential reputational damage if the vulnerability is exploited at scale.

REFERENCES

• https://github.com/discourse/discourse/security/advisories/GHSA-26p5-mjjh-wfcf
• https://nvd.nist.gov/vuln/detail/CVE-2025-48954