CVE-2026-57869: MicroRealEstate Auth Bypass Vulnerability

CVE-2026-57869 Overview

CVE-2026-57869 is a broken object-level access control vulnerability in MicroRealEstate, an open-source property management platform. The flaw affects all versions through 1.0.0-alpha3. Attackers can access documents uploaded by landlords or tenants without authorization. The issue compounds with a deterministic pattern used during random ID generation, which makes document identifiers predictable. An authenticated attacker with low privileges can enumerate and retrieve sensitive documents belonging to other users. This class of vulnerability is tracked as CWE-639: Authorization Bypass Through User-Controlled Key.

Critical Impact
Authenticated attackers can retrieve arbitrary tenant and landlord documents by predicting object identifiers, exposing personally identifiable information and financial records.

Affected Products

MicroRealEstate through version 1.0.0-alpha3
Landlord document storage endpoints
Tenant document storage endpoints

Discovery Timeline

2026-07-07 - CVE-2026-57869 published to NVD
2026-07-07 - Last updated in NVD database

Technical Details for CVE-2026-57869

Vulnerability Analysis

The vulnerability combines two defects in MicroRealEstate's document handling logic. First, document access endpoints fail to verify that the requesting user owns or has authorization to view the requested resource. Second, document identifiers are generated using a deterministic pattern rather than cryptographically secure randomness. Together, these defects let an authenticated attacker predict or enumerate document IDs and fetch files without an ownership check. Landlord and tenant document workflows in the platform typically contain leases, identification scans, payment records, and other sensitive materials.

Root Cause

The root cause is missing object-level authorization at the document retrieval layer. The application trusts a supplied document identifier without validating whether the current session belongs to the owning landlord or tenant. The predictable ID generation amplifies the impact because attackers do not need prior knowledge of valid identifiers. Refer to the The Missing Link Security Advisory for technical details.

Attack Vector

Exploitation requires network access to the MicroRealEstate application and a low-privileged authenticated account. The attacker enumerates document identifiers derived from the deterministic pattern, then issues authenticated requests to the document endpoints. Because ownership is not enforced, the server returns files belonging to other users. See the GitHub Project Repository for source-level context on the affected components.

Detection Methods for CVE-2026-57869

Indicators of Compromise

Repeated authenticated document requests from a single account targeting sequential or pattern-based document identifiers.
Access log entries showing one user retrieving documents linked to multiple unrelated landlord or tenant accounts.
Elevated download volume from accounts that historically accessed only their own resources.

Detection Strategies

Instrument the application to log the requesting user, the document owner, and the outcome of authorization checks for each retrieval.
Alert when a session accesses documents belonging to accounts outside its normal tenant or landlord scope.
Baseline document access patterns per role and flag deviations that indicate enumeration.

Monitoring Recommendations

Forward MicroRealEstate application and reverse-proxy logs to a centralized SIEM for correlation.
Monitor for HTTP 200 responses on document endpoints where the requesting user identifier does not match the resource owner.
Track error-to-success ratios on document endpoints, since enumeration often produces bursts of near-sequential requests.

How to Mitigate CVE-2026-57869

Immediate Actions Required

Restrict network exposure of MicroRealEstate instances running 1.0.0-alpha3 or earlier until a fix is applied.
Audit application logs for prior document access anomalies that match the enumeration pattern.
Rotate or invalidate document identifiers considered sensitive and notify affected landlords and tenants if exposure is confirmed.

Patch Information

At the time of publication, no fixed release is listed in the NVD entry for CVE-2026-57869. Monitor the GitHub Project Repository for updated releases and apply the patched version once available. Review the The Missing Link Security Advisory for remediation guidance from the reporting party.

Workarounds

Place MicroRealEstate behind an authenticating reverse proxy that enforces per-user access rules on document paths.
Add server-side middleware that validates the session owner against the document owner before returning file content.
Replace deterministic identifier generation with cryptographically secure random values, such as UUIDv4, for any new documents.

bash

# Example nginx snippet restricting document endpoints to internal networks during triage
location /documents/ {
    allow 10.0.0.0/8;
    deny all;
    proxy_pass http://microrealestate_backend;
}