CVE-2026-82582 in Shirasagi
Summary
by MITRE • 09/10/2026
An authorization bypass vulnerability exists in SHIRASAGI through a user-controlled key, which may allow an unauthorized attacker to retrieve files from the groupware's shared file feature.
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Analysis
by VulDB Data Team • 09/10/2026
The identified security flaw within the SHIRASAGI platform represents a critical failure in access control mechanisms, specifically categorized under CWE-285 Improper Authorization. This vulnerability stems directly from the application's handling of user-supplied input during requests to retrieve files via its shared file feature. Instead of validating whether the authenticated user possesses legitimate permissions for the specific resource being requested, the system relies on a user-controlled key that serves as the sole determinant of access rights. By manipulating this parameter, an attacker can bypass intended security restrictions and gain unauthorized read access to sensitive documents stored within the groupware environment.
From a technical perspective, the root cause lies in the lack of server-side authorization checks against the underlying file system or database records associated with the shared files. The application likely trusts the value provided by the client without cross-referencing it against an authoritative list of permissions assigned to the current session's user identity. This design pattern creates a direct path for insecure direct object references, where sequential or predictable identifiers are used to access resources without adequate verification. An attacker can exploit this by enumerating valid keys or guessing file identifiers to download content that was intended only for specific groups or individuals within the organization.
The operational impact of this vulnerability is significant, as it compromises the confidentiality and integrity of organizational data shared through SHIRASAGI. Unauthorized retrieval of files may expose proprietary information, personal identifiable information, or confidential business strategies to external adversaries. In a groupware context where collaboration relies on trust and controlled sharing, such a breach undermines the fundamental security model of the application. Attackers could potentially chain this access with other vulnerabilities to escalate privileges further or exfiltrate large volumes of data over time without detection, leading to severe regulatory compliance issues and reputational damage for the affected organization.
This type of vulnerability aligns closely with MITRE ATT&CK technique T1078 Valid Accounts, as it involves leveraging legitimate credentials but abusing their permissions through flawed logic rather than credential theft. It also relates to CWE-639 Authorization Bypass Through User-Controlled Key, highlighting the danger of relying on client-side or easily manipulable identifiers for security decisions. To mitigate this risk, developers must implement robust server-side authorization checks that verify the current user's relationship to every requested resource before granting access. This includes ensuring that shared file permissions are explicitly checked against a secure permission matrix rather than trusting external inputs. Additionally, implementing random, non-sequential identifiers for files and enforcing strict input validation can reduce the attack surface. Regular security audits focusing on access control logic and penetration testing specifically targeting authorization bypass scenarios are essential to maintain the integrity of the groupware's data sharing features.