CVE-2026-25811: PlaciPy Auth Bypass Vulnerability

CVE-2026-25811 Overview

CVE-2026-25811 is an Improper Authorization vulnerability (CWE-863) affecting PlaciPy, a placement management system designed for educational institutions. In version 1.0.0, the application derives the tenant identifier directly from the email domain provided by the user, without validating domain ownership or registration. This fundamental design flaw enables cross-tenant data access, allowing malicious users to potentially access sensitive placement data belonging to other educational institutions.

Critical Impact

Attackers can bypass tenant isolation by manipulating email domain input, potentially gaining unauthorized access to confidential student placement records, company partnerships, and institutional data across multiple tenants.

Affected Products

• PlaciPy version 1.0.0
• PlaciPy placement management system deployments using email domain-based tenant identification

Discovery Timeline

• 2026-02-09 - CVE-2026-25811 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-25811

Vulnerability Analysis

This vulnerability represents a classic Broken Access Control flaw where the application fails to properly validate tenant boundaries. The PlaciPy application uses a user-supplied email domain as the sole basis for determining which tenant's data a user should access. This design assumes that users can only provide email addresses from domains they legitimately own or are associated with, which is an inherently flawed assumption.

When a user registers or authenticates, the system extracts the domain portion of their email address (e.g., university.edu from student@university.edu) and uses this to route them to the corresponding tenant's data. Without proper domain ownership verification or email validation, an attacker can simply use any email address with a target institution's domain to gain access to that institution's placement data.

Root Cause

The root cause is the absence of domain ownership validation and proper tenant isolation controls. The application implicitly trusts user-provided input (the email domain) to determine authorization scope. This violates the principle of "never trust user input" and fails to implement proper tenant isolation mechanisms such as:

• Email verification workflows that confirm the user actually controls the email address
• Domain ownership verification (DNS-based or administrative approval)
• Administrative approval workflows for new user registrations
• Separate tenant enrollment processes independent of email domains

Attack Vector

The attack vector is network-based and requires low-privileged access (ability to register an account). An attacker can exploit this vulnerability through the following approach:

1. The attacker identifies a target educational institution using PlaciPy
2. The attacker registers a new account using a fabricated email address with the target institution's domain (e.g., attacker@targetuniversity.edu)
3. If email verification is weak or absent, the attacker gains access to the target tenant
4. The attacker can then view, and potentially modify, placement data belonging to the target institution

This attack requires no user interaction from victims and has low attack complexity. The vulnerability's network accessibility makes it exploitable remotely by any attacker who can reach the PlaciPy application.

Detection Methods for CVE-2026-25811

Indicators of Compromise

• Unusual user registrations with email domains that don't match expected organizational patterns
• Multiple failed or suspicious registration attempts using various institutional email domains
• Access patterns showing users querying data across multiple tenant contexts
• Audit logs revealing email addresses that fail subsequent delivery verification

Detection Strategies

• Implement logging and alerting for registration attempts using high-value institutional domains
• Monitor for anomalous data access patterns that span multiple logical tenant boundaries
• Deploy rate limiting on registration endpoints to prevent domain enumeration attacks
• Cross-reference registered email addresses against known institutional email directories where possible

Monitoring Recommendations

• Enable comprehensive audit logging for all user registration and authentication events
• Implement real-time alerting for registration spikes from specific email domains
• Monitor application logs for signs of data exfiltration following new account creation
• Review access patterns for newly registered accounts within the first 24-48 hours

How to Mitigate CVE-2026-25811

Immediate Actions Required

• Review all existing user accounts for suspicious email domain registrations
• Implement email verification that requires users to click a confirmation link sent to their claimed email address
• Consider temporarily disabling self-registration and requiring administrative approval for new accounts
• Audit access logs to identify any potential unauthorized cross-tenant data access

Patch Information

Users should consult the GitHub Security Advisory for the latest patch information and remediation guidance from the PlaciPy maintainers. Upgrade to a patched version when available from the Praskla Technology repository.

Workarounds

• Implement mandatory email verification requiring users to confirm ownership of their email address before granting tenant access
• Deploy an administrative approval workflow for all new user registrations
• Decouple tenant assignment from email domains by using invitation-based enrollment with administrative oversight
• Implement domain allowlisting to restrict registration to pre-approved email domains only

# Example: Nginx rate limiting configuration for registration endpoint
# Add to nginx.conf to limit registration attempts
limit_req_zone $binary_remote_addr zone=registration:10m rate=5r/m;

location /api/register {
    limit_req zone=registration burst=2 nodelay;
    proxy_pass http://placipy_backend;
}