CVE-2021-20840
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System...
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System versions prior to 1.5.11 allows a remote attacker to inject an arbitrary script via unspecified vectors.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System versions prior to 1.5.11 allows a remote attacker to inject an arbitrary script via unspecified vectors.
- Record
CVE-2021-20840- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
CVE List No score
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System versions prior to 1.5.11 allows a remote attacker to inject an arbitrary script via unspecified vectors.
- Record
CVE-2021-20840- Updated
- 2026-11-02
EUVDEUVD-2021-8252 No score
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System versions prior to 1.5.11 allows a remote attacker to inject an arbitrary script via unspecified vectors.
- Record
EUVD-2021-8252- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-6wcx-352r-rcj5
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System...
Cross-site scripting vulnerability in Booking Package - Appointment Booking Calendar System versions prior to 1.5.11 allows a remote attacker to inject an arbitrary script via unspecified vectors.
- Record
GHSA-6wcx-352r-rcj5- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-20840 is a medium vulnerability (CVSS 6.1) in Saasproject Booking Package - Appointment Booking Calendar System, published November 24, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.28%, the 70th percentile. No source names a fixed version.