CVE-2026-33541 — miraheze/ts-portal
MEDIUMCVE-2026-33541 is a medium-severity (CVSS 6.5) Uncontrolled Resource Consumption vulnerability in miraheze/ts-portal. A fix is available for miraheze/ts-portal — see the affected versions and patch details below.
TSPortal's Uncontrolled User Creation via Validation Side Effects Leads to Potential Denial of Service
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33541.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-33541 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
miraheze/ts-portalReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
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
- Submit a DPA request using an invalid username
- Ensure the request fails validation due to
MirahezeUsernameRule - 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
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | miraheze/ts-portal | all versions | 34composer require miraheze/ts-portal:^34 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for miraheze/ts-portal, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update miraheze/ts-portal to 34 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-33541 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33541 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33541. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33541 in your dependencies?
O3 Security finds CVE-2026-33541 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.