CVE-2026-86274 in siga
Summary
by MITRE • 09/07/2026
A security vulnerability has been detected in projeto-siga siga up to 11.0.2.10/11.0.2.13/11.1.1. This affects the function ExAutenticacaoController.autenticar of the file sigaex/src/main/java/br/gov/jfrj/siga/vraptor/ExAutenticacaoController.java of the component Authentication Flow. Such manipulation of the argument cod/jwt leads to missing authorization. The attack may be launched remotely. The exploit has been disclosed publicly and may be used. The project was informed of the problem early through an issue report but has not responded yet.
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Analysis
by VulDB Data Team • 09/07/2026
The identified vulnerability resides within the authentication flow component of projeto-siga, specifically affecting versions up to 11.0.2.10, 11.0.2.13, and 11.1.1. The flaw is located in the ExAutenticacaoController.autenticar function found in the file sigaex/src/main/java/br/gov/jfrj/siga/vraptor/ExAutenticacaoController.java. This component serves as a critical gatekeeper for user access, responsible for validating credentials and establishing session states before granting entry to protected resources. The vulnerability stems from improper validation logic within this controller method, which fails to correctly enforce authorization checks when processing specific input arguments related to the cod/jwt parameter.
The technical nature of this flaw is classified as a missing authorization issue, corresponding directly to CWE-862 in the Common Weakness Enumeration standard. In a properly secured application, every request must be verified against the user's permissions and authentication status before any sensitive operation or data access occurs. However, due to the defect in the ExAutenticacaoController.autenticar method, an attacker can manipulate the cod/jwt argument to bypass these checks entirely. This manipulation allows unauthorized entities to authenticate as valid users without possessing legitimate credentials or tokens. The root cause lies in the application's failure to verify that the provided JWT (JSON Web Token) is both syntactically correct and cryptographically signed by a trusted authority, combined with insufficient server-side validation of the token's claims before granting access.
From an operational perspective, this vulnerability poses a severe risk to the confidentiality and integrity of the system. Because the attack vector is remote, adversaries can exploit this flaw over a network without requiring prior local access or physical proximity to the target infrastructure. The ability to bypass authentication mechanisms effectively nullifies the primary defense layer of the application. Once an attacker successfully exploits this missing authorization gap, they gain unauthorized access to the application as any user whose identity was spoofed through the manipulated token. This can lead to data breaches, where sensitive government or personal information is exfiltrated, and potential privilege escalation if the compromised account holds administrative roles. The impact extends beyond immediate data loss, potentially compromising the trustworthiness of the entire digital service provided by projeto-siga.
The exploit for this vulnerability has been disclosed publicly, which significantly increases the likelihood of active exploitation in the wild. Public disclosure removes the barrier to entry for less sophisticated attackers who may not possess advanced reverse-engineering skills but can utilize existing proof-of-concept code or automated scanning tools designed to target known authentication bypass patterns. The fact that the project maintainers have been informed via an issue report yet have not responded indicates a potential gap in security maintenance and patch management processes. This lack of timely response leaves users exposed for an extended period, as there is no official fix available through standard update channels at this time.
To mitigate the risks associated with this vulnerability, immediate action is required from system administrators and developers maintaining projeto-siga installations. The most effective mitigation involves upgrading to a patched version once one becomes available from the project maintainers. In the interim, organizations should implement compensating controls such as strict input validation on all JWT-related parameters at the API gateway or reverse proxy level before requests reach the application server. Additionally, enabling comprehensive logging and monitoring for authentication failures can help detect attempts to exploit this flaw in real-time. Security teams should also review access logs for anomalous login patterns that do not correspond with expected user behavior, as these may indicate active exploitation of the missing authorization check. Until a patch is released, restricting network exposure of the affected endpoints to trusted IP ranges or implementing multi-factor authentication at an external layer can provide additional layers of defense against unauthorized access attempts aligned with ATT&CK techniques for credential manipulation and initial access.