CVE-2025-55736 is a critical security vulnerability identified in the DogukanUrker FlaskBlog application, specifically affecting versions 2.8.0 and earlier. FlaskBlog is a blogging platform built using the Flask web framework. The vulnerability is categorized under CWE-425 (Direct Request or Forced Browsing) and CWE-807 (Improper Control of a Resource Through its Lifetime). The core issue lies in the application's route handling, particularly in the 'routes/adminPanelUsers' file, where an arbitrary user can manipulate requests to escalate their privileges by changing their role to 'admin' without any authentication or authorization checks. This privilege escalation flaw allows an attacker to gain administrative rights, enabling them to perform critical actions such as deleting users, posts, comments, and potentially other administrative functions. The vulnerability is exploitable remotely without any user interaction or prior authentication, as indicated by the CVSS 4.0 vector: AV:N/AC:L/AT:N/PR:N/UI:N, which means network attack vector, low attack complexity, no authentication or user interaction required. The impact on confidentiality and integrity is high, as attackers can manipulate or delete data and control user accounts. Availability impact is not significant per the CVSS vector. No known exploits are reported in the wild yet, but the critical severity score of 9.3 underscores the urgent need for remediation. The flaw arises from insufficient access control and improper validation of user roles within the application logic, allowing direct forced browsing or direct requests to sensitive endpoints that should be restricted to administrators only.

For European organizations using FlaskBlog version 2.8.0 or earlier, this vulnerability poses a severe risk. An attacker exploiting this flaw can gain full administrative privileges, compromising the integrity and confidentiality of the blog platform's data. This includes unauthorized deletion or modification of user accounts, posts, and comments, which can lead to data loss, reputational damage, and potential regulatory non-compliance, especially under GDPR mandates concerning data protection and breach notification. The ability to escalate privileges without authentication means that any exposed instance of the vulnerable FlaskBlog is at immediate risk of compromise. This could be particularly damaging for organizations relying on FlaskBlog for internal communications or public-facing content, as attackers could deface websites, spread misinformation, or disrupt operations. Additionally, compromised admin accounts could be leveraged to pivot attacks within the network or to implant further malicious code, increasing the threat scope. The lack of known exploits in the wild does not diminish the urgency, as the vulnerability is straightforward to exploit given the low complexity and no required privileges.

1. Immediate upgrade: Organizations should upgrade FlaskBlog to a version later than 2.8.0 where this vulnerability is patched. If no patch is available yet, consider applying custom access control checks to restrict role changes strictly to authorized administrators. 2. Implement strict server-side authorization: Ensure that all role changes and administrative actions are validated server-side with proper authentication and authorization checks, disallowing direct requests that bypass these controls. 3. Harden route access: Restrict access to sensitive routes such as 'adminPanelUsers' using authentication middleware and role-based access control (RBAC) mechanisms. 4. Monitor logs: Enable detailed logging and monitoring of access to administrative endpoints to detect suspicious activities indicative of forced browsing or privilege escalation attempts. 5. Web Application Firewall (WAF): Deploy or update WAF rules to detect and block unauthorized attempts to access admin routes or manipulate user roles. 6. Conduct security audits: Perform code reviews and penetration testing focused on access control mechanisms to identify and remediate similar vulnerabilities. 7. User education and incident response: Prepare incident response plans for potential exploitation and educate administrators on recognizing signs of compromise.