HOMEVULNERABILITIESCVE-2021-42663
MEDIUM

CVE-2021-42663

CWE-79Published: November 5, 2021· Updated: Jun 17, 2026

4.3
CVSS v3.1

Official Description

An HTML injection vulnerability exists in Sourcecodester Online Event Booking and Reservation System in PHP/MySQL via the msg parameter to /event-management/index.php. An attacker can leverage this vulnerability in order to change the visibility of the website. Once the target user clicks on a given link he will display the content of the HTML code of the attacker's choice.

NVD Source

Technical Analysis

CVE-2021-42663 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionRequired
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Affected Vendors & Products

online_event_booking_and_reservation_system_project1 product(s)
online event booking and reservation system
Source: NVD CPE · 1 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://github.com/TheHackingRabbi/CVE-2021-42663
ADVISORYhttps://www.sourcecodester.com/php/14241/online-event-booking-and-reservation-system-phpmysql.html
ADVISORYhttps://github.com/TheHackingRabbi/CVE-2021-42663
ADVISORYhttps://www.sourcecodester.com/php/14241/online-event-booking-and-reservation-system-phpmysql.html

All References (4)

→
https://github.com/TheHackingRabbi/CVE-2021-42663Exploit · Third Party Advisory
→
https://www.sourcecodester.com/php/14241/online-event-booking-and-reservation-system-phpmysql.htmlProduct · Third Party Advisory
→
https://github.com/TheHackingRabbi/CVE-2021-42663Exploit · Third Party Advisory
→
https://www.sourcecodester.com/php/14241/online-event-booking-and-reservation-system-phpmysql.htmlProduct · Third Party Advisory

Quick Facts

CVE IDCVE-2021-42663
CVSS Score4.3 / 10
SeverityMEDIUM
WeaknessCWE-79
CISA KEVNo
Affected1 vendor(s)
PublishedNov 5, 2021

Related CVEs (CWE-79)

CVE-2023-0776
10.0
CVE-2021-32671
10.0
CVE-2026-54433
10.0
CVE-2024-6886
10.0
CVE-2025-49410
10.0
CVE-2011-3046
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-42663 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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