EUVD-2026-72853
GHSA-v26j-p538-j93h
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Timing oracle attacks require controlled network conditions and many samples, warranting AC:H; no authentication needed as the callback endpoint is publicly accessible by design.
Primary rating from Vendor (TR-CERT).
CVSS VectorNVD
Lifecycle Timeline
2DescriptionNVD
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.
AnalysisAI
Timing side-channel in the PayTR Virtual Pos iFrame API (v9x) WHMCS Module (v9.0.0-v9.0.3) enables unauthenticated remote attackers to perform black-box reverse engineering of internal secret values - such as HMAC keys or API signing tokens - by measuring statistically distinguishable response-time differences across repeated crafted requests. The CWE-208 root cause is a non-constant-time comparison operation in the module's payment verification logic, which leaks information about secret material byte-by-byte through observable latency variations. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | The PayTR Virtual Pos iFrame API (v9x) WHMCS Module must be installed and active on a WHMCS instance running a version between v9.0.0 and v9.0.2 inclusive. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The provided CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N = 7.5) overstates exploitability by assigning AC:L. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade the PayTR Virtual Pos iFrame API (v9x) WHMCS Module to v9.0.3 or later, which is the vendor-released patched version per the TR-CERT advisory at https://siberguvenlik.gov.tr/guvenlik-bildirimleri/detay/tr-26-1034. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify and inventory all WHMCS installations running PayTR Virtual Pos module versions 9.0.0-9.0.3, and document the network exposure of affected payment verification endpoints. …
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Payment-confirmation forgery in PayTR's Virtual Pos iFrame API (v9x) WHMCS Module (v9.0.0 to before v9.0.3) lets remote
Input data manipulation in the PayTR Virtual Pos iFrame API (v9x) WHMCS Module versions 9.0.0 through 9.0.2 allows unaut
Same weakness CWE-208 – Observable Timing Discrepancy
View allSame technique Information Disclosure
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External POC / Exploit Code
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