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CVE-2021-42663

26
FAUCET Score

CVE-2021-42663 is an HTML injection vulnerability affecting Sourcecodester Online Event Booking and Reservation System in PHP/MySQL. Specifically, it allows an attacker to inject arbitrary HTML via the 'msg' parameter in 'index.php', altering website visibility for a targeted user who clicks a malicious link. This vulnerability has a CVSS score of 4.3 (Medium) due to its network-based attack vector and reliance on user interaction, potentially leading to information disclosure. While there is no evidence of active exploitation or Metasploit modules, a Nuclei template exists, and community discussion and media coverage are minimal.

Impacted Technologies

VendorProductVersion(s)CPE
2.3.0CPE matchmatch criteria
cpe:2.3:a:online_event_booking_and_reservation_system_project:online_event_booking_and_reservation_system:2.3.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

4.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.79%
Probability of exploitation in next 30 days
EPSS Percentile
88.9%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
Nuclei: CVE-2021-42663 · Sep 3, 2022
This CVE's current EPSS score of 0.0379 is in the 95th percentile among its peer group of 26,234 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Remediation records are not available for this CVE.

References

github.com / TheHackingRabbi/CVE-2021-42663
ExploitThird Party Advisory
sourcecodester.com / php/14241/online-event-booking-and-reservation-system-phpmysql.html
ProductThird Party Advisory