Skip to content
Fencer Vulns
critical 9.8

CVE-2021-42077 json

PHP Event Calendar before 2021-09-03 allows SQL injection, as demonstrated by the /server/ajax/user_manager.php username parameter.

published 2021-11-08 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-29063

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

PHP Event Calendar before 2021-09-03 allows SQL injection, as demonstrated by the /server/ajax/user_manager.php username parameter. This can be used to execute SQL statements directly on the database, allowing an adversary in some cases to completely compromise the database system. It can also be used to bypass the login form.

Patch / fix

  • kaysongroup php_event_calendar 2021-09-03

Exploit prediction

2.51% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • packetstormsecurity.com http://packetstormsecurity.com/files/164777/PHP-Event-Calendar-Lite-Edition-SQL-Injection.html referenced PoC, tagged "exploit" by a source, unverified
  • syss.de https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2021-048.txt referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-89 Improper Neutralization of Special Elements used in an SQL Command

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.