CVE-2026-82582 Overview
CVE-2026-82582 is an authorization bypass vulnerability in SHIRASAGI, an open-source groupware and content management platform. The flaw resides in the shared file feature, where access decisions rely on a user-controlled key. An authenticated attacker with low privileges can manipulate this key to retrieve files belonging to other users or groups. The issue is classified under CWE-639: Authorization Bypass Through User-Controlled Key.
Critical Impact
Authenticated attackers can retrieve confidential files from SHIRASAGI's shared file feature by tampering with a user-controlled identifier, bypassing intended access restrictions.
Affected Products
- SHIRASAGI groupware (see SS Project Support Document #1710 for version details)
- Deployments exposing the shared file feature to authenticated users
- Instances running versions prior to the vendor-supplied fix referenced in JVN37476837
Discovery Timeline
- 2026-09-10 - CVE-2026-82582 published to NVD
- 2026-09-10 - Last updated in NVD database
Technical Details for CVE-2026-82582
Vulnerability Analysis
The vulnerability is an Insecure Direct Object Reference (IDOR) in SHIRASAGI's shared file feature. The application uses an identifier supplied by the requester to look up file resources but fails to validate whether the requester is authorized to access the referenced object. As a result, an attacker who can authenticate with any low-privileged account can enumerate or guess file keys and retrieve files that should be restricted to other users or groups.
Because the exploit path requires only a valid session and a modified request parameter, no elevated privileges or user interaction are needed. The impact is limited to confidentiality of stored files; integrity and availability of the platform are not directly affected.
Root Cause
The root cause is missing server-side authorization checks on file retrieval requests. SHIRASAGI trusts a user-controlled key when resolving the target file object and does not confirm that the authenticated principal has permission to access the requested resource. This design pattern maps directly to CWE-639, where security decisions depend on data the attacker can modify.
Attack Vector
Exploitation occurs over the network against the SHIRASAGI web interface. An attacker authenticates as a low-privileged user, then issues requests to the shared file endpoint with a modified file identifier referencing another user's or group's resource. The server returns the file contents without enforcing group or ownership checks. Refer to the JVN Security Advisory JVN37476837 for the vendor-confirmed exploitation profile.
No verified public exploit code is available at the time of publication. The vulnerability mechanism is described in prose only.
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Stop Identity AttacksDetection Methods for CVE-2026-82582
Indicators of Compromise
- Web access logs showing a single authenticated session requesting many distinct shared file identifiers in a short interval.
- HTTP requests to SHIRASAGI shared file endpoints where the file key does not correspond to any resource previously created or accessed by that user.
- Unexpected 200 OK responses on file download endpoints for accounts that historically only access a narrow set of resources.
Detection Strategies
- Baseline normal shared file access patterns per user and alert on statistical outliers in request volume or resource diversity.
- Instrument the shared file endpoint to log the requesting user, target file owner, and target group, then flag mismatches.
- Correlate authentication events with shared file download activity to identify newly created or dormant accounts probing file identifiers.
Monitoring Recommendations
- Forward SHIRASAGI web server and application logs to a centralized logging or SIEM platform for retention and query.
- Monitor for enumeration behavior such as sequential or high-entropy variations of file key parameters.
- Review audit trails for file access events attributed to accounts outside the file owner's group or department.
How to Mitigate CVE-2026-82582
Immediate Actions Required
- Apply the vendor-supplied update referenced in SS Project Support Document #1710 as soon as it is available in your environment.
- Restrict network access to the SHIRASAGI application to trusted users and networks while patching is scheduled.
- Audit shared file access logs for anomalous retrieval activity predating the patch deployment.
Patch Information
The SS Project has published remediation guidance in SS Project Support Document #1710 and coordinated disclosure through JVN37476837. Administrators should upgrade SHIRASAGI to the fixed release identified in those advisories and verify that the shared file feature enforces server-side authorization after the update.
Workarounds
- Disable or restrict the shared file feature for non-essential users until the patch is applied.
- Rotate or invalidate any shared file identifiers that may have been exposed if unauthorized access is suspected.
- Enforce least-privilege group membership so that low-privileged accounts cannot reach sensitive shared file content even if authorization is bypassed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
