Callback Authentication Bypass via Timing Attack in PayTR's PayTR Virtual Pos iFrame API (v9x) WHMCS Module (CVE-2026-16037) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-16037

Callback Authentication Bypass via Timing Attack in PayTR's PayTR Virtual Pos iFrame API (v9x) WHMCS Module

Answer in brief

CVE-2026-16037 records a Unknown severity vulnerability in Callback Authentication Bypass via Timing Attack in PayTR's PayTR Virtual Pos iFrame API (v9x) WHMCS Module. The current sources do not mark it as known exploited. The current feed maps PayTR Payment and Electronic Money Institution Inc./PayTR Virtual Pos iFrame API (v9x) WHMCS Module (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 8, 2026Updated Sep 8, 2026Source checked Sep 8, 2026First seen by HOL Sep 8, 2026Material review Sep 8, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps PayTR Payment and Electronic Money Institution Inc./PayTR Virtual Pos iFrame API (v9x) WHMCS Module (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
PayTR Payment and Electronic Money Institution Inc./PayTR Virtual Pos iFrame API (v9x) WHMCS Modulegeneric	>=v9.0.0 <v9.0.3	v9.0.3

Recommended response

Check inventory. Check lockfiles and deployed manifests for PayTR Payment and Electronic Money Institution Inc./PayTR Virtual Pos iFrame API (v9x) WHMCS Module.
Review the reported fix. Update PayTR Payment and Electronic Money Institution Inc./PayTR Virtual Pos iFrame API (v9x) WHMCS Module to v9.0.3 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 8, 2026

Sources and claim methodology

Source referencesiberguvenlik.gov.tr

Upstream source description

Observable timing discrepancy vulnerability in PayTR Payment and Electronic Money Institution Inc. PayTR Virtual Pos iFrame API (v9x) WHMCS Module allows Black Box Reverse Engineering. This issue affects PayTR Virtual Pos iFrame API (v9x) WHMCS Module: from v9.0.0 before v9.0.3.

Quoted source text, attributed separately from HOL analysis.