VulnerabilityPublished 9 Apr 2026Updated 13 Apr 2026

CVE-2026-2519: Online Scheduling and Appointment Booking System (WordPress plugin) · External Control of Assumed-Immutable Web Parameter

Affects Online Scheduling and Appointment Booking System (WordPress plugin)Source CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 9 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
ladelaOnline Scheduling and Appointment Booking System – Bookly	Affected <=27.0	Fixed in–

AI-suggested

Until an official fix is released, users should consider implementing server-side validation for the 'tips' parameter to reject negative values or disable the tips feature if possible. Monitoring for suspicious transactions related to price anomalies may also help mitigate risk.

Description

The Online Scheduling and Appointment Booking System – Bookly plugin for WordPress is vulnerable to price manipulation via the 'tips' parameter in all versions up to, and including, 27.0. This is due to the plugin trusting a user-supplied input without server-side validation against the configured price. This makes it possible for unauthenticated attackers to submit a negative number to the 'tips' parameter, causing the total price to be reduced to zero.

Impact

The vulnerability allows unauthenticated attackers to manipulate the total price by submitting negative values in the 'tips' parameter, potentially bypassing payment requirements or causing financial loss to merchants using the plugin. There is no impact on confidentiality or availability reported. The integrity of the pricing calculation is compromised, which can lead to unauthorized price reductions.

Summary

CVE-2026-2519 describes a vulnerability in the ladela Online Scheduling and Appointment Booking System – Bookly WordPress plugin. The flaw arises from the plugin's failure to validate the 'tips' parameter on the server side, allowing unauthenticated attackers to submit negative values. This external control of an assumed-immutable parameter enables attackers to manipulate the total price calculation, effectively reducing it to zero. The vulnerability affects all versions up to 27.0. The CVSS score of 5.3 reflects a medium severity impact with no confidentiality or availability impact but with integrity impact due to price manipulation.

CWE-472External Control of Assumed-Immutable Web Parameter (opens in a new tab)
Base weaknessOWASP Top 10 A06:2025: Insecure Design (opens in a new tab)
The web application does not sufficiently verify inputs that are assumed to be immutable but are actually externally controllable, such as hidden form fields.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Implementation · Input Validation
Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174).
OWASP Cheat Sheets
Secure Design Principles (opens in a new tab)
Attack patterns
XML Schema Poisoning (opens in a new tab)
Session Credential Falsification through Manipulation (opens in a new tab)
Accessing/Intercepting/Modifying HTTP Cookies (opens in a new tab)
Manipulating Opaque Client-based Data Tokens (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 17 Apr 2026, 12:03 UTC

WeaknessesCWE-472

Technical details

References

Community reviews

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