CVE-2026-102248 in Rebuild
Summary
by MITRE • 09/29/2026
A vulnerability was identified in Rebuild up to 4.4.7/4.5.0-beta5. This affects an unknown part of the file /user/login of the component Login Endpoint. The manipulation leads to improper authentication. It is possible to initiate the attack remotely. The exploit is publicly available and might be used. The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 09/29/2026
The identified vulnerability resides within the Rebuild framework, specifically affecting versions up through 4.4.7 and the beta release 4.5.0-beta5. This security flaw is located in the /user/login endpoint, which serves as a critical component for user authentication processes. The nature of this defect constitutes an improper authentication mechanism, allowing attackers to bypass standard identity verification procedures. Such vulnerabilities are typically classified under CWE-287, Improper Authentication, and often align with ATT&CK technique T1078, Valid Accounts, when exploited by adversaries seeking unauthorized access to systems or data. The core technical issue involves a failure in the login logic that permits authentication bypass, potentially due to flawed validation of credentials, session management errors, or insufficient checks on request parameters during the initial handshake phase.
The operational impact of this vulnerability is severe, as it directly compromises the integrity of user identity verification. An attacker who successfully exploits this flaw can gain unauthorized access to protected resources without possessing valid credentials. This capability effectively nullifies the security perimeter established by the application's login mechanism. Since the exploit is publicly available, the risk landscape has shifted from theoretical possibility to immediate practical threat. Automated scanning tools and malicious actors actively monitor for such public exploits, significantly increasing the likelihood of successful intrusion attempts against unpatched systems. The absence of a vendor response further exacerbates this risk, leaving administrators without official guidance or patches to remediate the issue promptly.
Remote exploitation capability means that an attacker can initiate these attacks from any network location with internet connectivity, removing the need for local access or physical proximity to the target system. This remote accessibility makes the vulnerability particularly dangerous in web-facing applications where the login endpoint is exposed to the public internet. The combination of a publicly available exploit and the critical nature of authentication bypass creates a high-severity threat vector that can lead to data breaches, privilege escalation, and complete compromise of affected environments if left unaddressed.
Mitigation strategies must be implemented immediately given the lack of vendor support. Organizations should prioritize applying any available workarounds or configuration changes that restrict access to the /user/login endpoint until a patch is released by the vendor. Implementing web application firewalls with rules specifically targeting authentication bypass patterns can provide an additional layer of defense. Additionally, enforcing multi-factor authentication adds a secondary verification step that may mitigate the impact even if the primary credential check is bypassed. Continuous monitoring for anomalous login attempts and strict rate limiting on the login endpoint are also recommended to reduce the effectiveness of automated exploitation tools. Regular security assessments and penetration testing should be conducted to identify similar weaknesses in other parts of the application architecture, ensuring a holistic approach to securing authentication mechanisms against evolving threats.