CVE-2026-86838: CWE-472 External Control of Assumed-Immutable Web Parameter in Bookly
The Bookly WordPress plugin before 28.3 does not validate client-supplied booking quantity values on the server before computing the appointment total, allowing unauthenticated users to reduce the total to zero and book paid services for free while bypassing the payment step.
AI Analysis
Technical Summary
The Bookly WordPress plugin prior to version 28.3 does not validate client-supplied booking quantity values on the server side before calculating the appointment total. This lack of validation allows unauthenticated attackers to externally control a parameter that should be immutable, effectively reducing the total cost to zero and bypassing payment requirements for booking paid services.
Potential Impact
An attacker can book paid services for free by manipulating the booking quantity parameter, resulting in loss of revenue. The vulnerability does not impact confidentiality or availability but affects the integrity of the payment process.
Mitigation Recommendations
Upgrade the Bookly plugin to version 28.3 or later where this issue is fixed. Since the vulnerability is patched in version 28.3, applying this official fix will remediate the risk.
CVE-2026-86838: CWE-472 External Control of Assumed-Immutable Web Parameter in Bookly
Description
The Bookly WordPress plugin before 28.3 does not validate client-supplied booking quantity values on the server before computing the appointment total, allowing unauthenticated users to reduce the total to zero and book paid services for free while bypassing the payment step.
CVSS v3.1
Score 5.3medium
Affected software
Bookly
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Bookly WordPress plugin prior to version 28.3 does not validate client-supplied booking quantity values on the server side before calculating the appointment total. This lack of validation allows unauthenticated attackers to externally control a parameter that should be immutable, effectively reducing the total cost to zero and bypassing payment requirements for booking paid services.
Potential Impact
An attacker can book paid services for free by manipulating the booking quantity parameter, resulting in loss of revenue. The vulnerability does not impact confidentiality or availability but affects the integrity of the payment process.
Mitigation Recommendations
Upgrade the Bookly plugin to version 28.3 or later where this issue is fixed. Since the vulnerability is patched in version 28.3, applying this official fix will remediate the risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- WPScan
- Date Reserved
- 2026-09-08T14:42:34.349Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aba0dbef7a7c541064c334e
Added to database: 09/28/2026, 06:48:30 UTC
Last enriched: 09/28/2026, 07:03:21 UTC
Last updated: 09/29/2026, 01:57:22 UTC
Views: 17
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