CVE-2026-2543 in vichan
Summary
by MITRE • 02/16/2026
A vulnerability was identified in vichan-devel vichan up to 5.1.5. This vulnerability affects unknown code of the file inc/mod/pages.php of the component Password Change Handler. The manipulation of the argument Password leads to unverified password change. The attack can be initiated remotely. The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 02/20/2026
This vulnerability resides within the vichan-devel vichan software version 5.1.5 and earlier, specifically targeting the password change functionality implemented in the inc/mod/pages.php file. The flaw manifests when handling the Password argument during the password change process, creating a critical security gap that allows unauthorized modifications to user accounts. The vulnerability represents a failure in input validation and authentication verification mechanisms, enabling attackers to manipulate the password change handler without proper authorization. The attack vector is remotely exploitable, meaning malicious actors can initiate the exploit from external networks without requiring physical access to the system. This remote accessibility significantly amplifies the potential impact, as attackers can target vulnerable installations from anywhere on the internet. The lack of vendor response to early disclosure attempts suggests either insufficient security monitoring or delayed acknowledgment of the vulnerability's severity, leaving affected systems exposed for extended periods without official patches or mitigations.
The technical nature of this vulnerability aligns with CWE-287, which addresses improper authentication issues in software systems. This weakness specifically enables unauthorized password changes through manipulation of the Password argument parameter, creating a direct path for account takeover attacks. The flaw operates as an authentication bypass mechanism, allowing attackers to circumvent normal password change procedures that should require verification of existing credentials or authorization tokens. The absence of proper input sanitization and validation means that the system accepts manipulated password values without sufficient verification steps. This vulnerability can be classified under the ATT&CK framework as a credential access technique, specifically targeting password modification capabilities within web applications. The attack requires minimal privileges to initiate, as the remote nature of the exploit means that even unauthenticated users could potentially manipulate password change handlers if the application lacks proper access controls.
The operational impact of this vulnerability extends beyond simple account compromise, as successful exploitation could lead to complete system infiltration and unauthorized access to sensitive data. Attackers could leverage compromised accounts to gain access to administrative functions, potentially leading to full system control and data exfiltration. The vulnerability's presence in the password change handler suggests that it could be exploited repeatedly, allowing attackers to modify multiple accounts over time without detection. Organizations relying on affected vichan installations face significant risk of unauthorized access, data breaches, and potential regulatory compliance violations. The remote exploit capability means that attackers don't need to be physically present or have network access to the target environment, making detection and prevention more challenging. This vulnerability essentially undermines the fundamental security principle of ensuring that only authorized users can modify account credentials, creating a persistent threat vector that could remain active until patched or mitigated.
Organizations must implement immediate mitigations to protect against exploitation of this vulnerability while awaiting official patches from the vichan development team. The most effective immediate response involves implementing additional authentication layers and access controls around password change functions, including requiring multi-factor authentication for sensitive operations and implementing rate limiting to prevent brute force attempts. Network-level protections should include firewall rules that restrict access to password change endpoints and monitoring for unusual authentication patterns. The implementation of proper input validation and parameter sanitization should be prioritized to prevent manipulation of the Password argument. Organizations should also consider implementing intrusion detection systems that can identify attempts to exploit this specific vulnerability pattern, monitoring for unusual password change activities that could indicate exploitation attempts. A comprehensive security audit of all authentication mechanisms within the affected software is essential to identify additional weaknesses that may have been overlooked. The lack of vendor response necessitates proactive security measures, including potential temporary workarounds such as disabling password change functionality until a proper patch is available, though this may impact legitimate user access and should be carefully balanced against security requirements.