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CVE-2026-33541

TSPortal's Uncontrolled User Creation via Validation Side Effects Leads to Potential Denial of Service

6.5 MediumFix available

TSPortal is the WikiTide Foundation’s in-house platform used by the Trust and Safety team to manage reports, investigations, appeals, and transparency work. Prior to version 34, a flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS). Version 34 contains a fix for the issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.30%Up 0.3 points since Mar 27, 2026
90%50%10%1%

What each source reports

CVE List Score used 6.5

TSPortal's Uncontrolled User Creation via Validation Side Effects Leads to Potential Denial of Service

TSPortal is the WikiTide Foundation’s in-house platform used by the Trust and Safety team to manage reports, investigations, appeals, and transparency work. Prior to version 34, a flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS). Version 34 contains a fix for the issue.

Record
CVE-2026-33541
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02
EUVDEUVD-2026-16398 6.5

TSPortal is the WikiTide Foundation’s in-house platform used by the Trust and Safety team to manage reports, investigations, appeals, and transparency work. Prior to version 34, a flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS). Version 34 contains a fix for the issue.

Record
EUVD-2026-16398
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-f346-8rp3-4h9h 6.5

TSPortal's Uncontrolled User Creation via Validation Side Effects Leads to Potential Denial of Service

Summary

A flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS).

Details

When submitting a Data Processing Agreement (DPA) request in TSPortal, the DPAAlreadyLive validation rule previously called User::findOrCreate().

This method created a user record if one did not already exist.

Although username validation (via MirahezeUsernameRule) correctly rejected invalid usernames, the DPAAlreadyLive rule was still executed during validation. Because it performed a state-changing operation, it created user records even when the overall validation failed and no DPA was created.

As a result:

  • Validation correctly rejected invalid input
  • However, user records were still inserted into the database as a side effect

These records were created:

  • Without a successful DPA request
  • Without audit logging tied to a completed action
  • Without visibility into their origin

Impact

An attacker could exploit this behavior by automating requests with invalid usernames, resulting in:

  • Mass creation of arbitrary user records
  • Unbounded database growth
  • Increased storage and indexing overhead
  • Potential degradation of application performance

At scale, this could lead to a denial of service condition due to resource exhaustion.

Proof of Concept

  1. Submit a DPA request using an invalid username
  2. Ensure the request fails validation due to MirahezeUsernameRule
  3. Observe that a corresponding user record is still created in the database

This behavior was confirmed prior to remediation.

Root Cause

The issue stemmed from:

  • Performing state-changing operations (findOrCreate) inside validation logic
  • Validation rules executing regardless of overall validation success
  • Lack of separation between validation and persistence layers

Mitigation

The issue has been fixed by removing database write operations from validation logic.

Specifically:

  • Replaced User::findOrCreate() with a non-mutating lookup (User::firstWhere(...))
  • Ensured validation rules only perform read operations
  • Prevented user creation unless all validation passes
Record
GHSA-f346-8rp3-4h9h
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02
NVD 6.5

TSPortal is the WikiTide Foundation’s in-house platform used by the Trust and Safety team to manage reports, investigations, appeals, and transparency work. Prior to version 34, a flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS). Version 34 contains a fix for the issue.

Record
CVE-2026-33541
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02
OSV 6.5

TSPortal's Uncontrolled User Creation via Validation Side Effects Leads to Potential Denial of Service

TSPortal is the WikiTide Foundation’s in-house platform used by the Trust and Safety team to manage reports, investigations, appeals, and transparency work. Prior to version 34, a flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS). Version 34 contains a fix for the issue.

Record
CVE-2026-33541
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02
OSVGHSA-f346-8rp3-4h9h 6.5

TSPortal's Uncontrolled User Creation via Validation Side Effects Leads to Potential Denial of Service

Summary

A flaw in TSPortal allowed attackers to create arbitrary user records in the database by abusing validation logic. While validation correctly rejected invalid usernames, a side effect within a validation rule caused user records to be created regardless of whether the request succeeded. This could be exploited to cause uncontrolled database growth, leading to a potential denial of service (DoS).

Details

When submitting a Data Processing Agreement (DPA) request in TSPortal, the DPAAlreadyLive validation rule previously called User::findOrCreate().

This method created a user record if one did not already exist.

Although username validation (via MirahezeUsernameRule) correctly rejected invalid usernames, the DPAAlreadyLive rule was still executed during validation. Because it performed a state-changing operation, it created user records even when the overall validation failed and no DPA was created.

As a result:

  • Validation correctly rejected invalid input
  • However, user records were still inserted into the database as a side effect

These records were created:

  • Without a successful DPA request
  • Without audit logging tied to a completed action
  • Without visibility into their origin

Impact

An attacker could exploit this behavior by automating requests with invalid usernames, resulting in:

  • Mass creation of arbitrary user records
  • Unbounded database growth
  • Increased storage and indexing overhead
  • Potential degradation of application performance

At scale, this could lead to a denial of service condition due to resource exhaustion.

Proof of Concept

  1. Submit a DPA request using an invalid username
  2. Ensure the request fails validation due to MirahezeUsernameRule
  3. Observe that a corresponding user record is still created in the database

This behavior was confirmed prior to remediation.

Root Cause

The issue stemmed from:

  • Performing state-changing operations (findOrCreate) inside validation logic
  • Validation rules executing regardless of overall validation success
  • Lack of separation between validation and persistence layers

Mitigation

The issue has been fixed by removing database write operations from validation logic.

Specifically:

  • Replaced User::findOrCreate() with a non-mutating lookup (User::firstWhere(...))
  • Ensured validation rules only perform read operations
  • Prevented user creation unless all validation passes
Record
GHSA-f346-8rp3-4h9h
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-400, CWE-770
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
miraheze/ts-portal
Packagist
through 33
34
miraheze/ts-portal
Packagist
before 34, plus listed versions
v1v10v11v12v13
Show 28 moreShow less
v14v15v16v17v18v19v2v20v21v22v23v24v25v26v27v28v29v3v30v31v32v33v4v5v6v7v8v9
34

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-33541 is a medium vulnerability (CVSS 6.5) in Miraheze Tsportal, published March 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 23rd percentile. Fixed in miraheze/ts-portal 34.

References

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