CVE-2021-41930: Cross site scripting (XSS) vulnerability in Sourcecodester Online Covid Vaccination Scheduler System v1 by ore

This month

MEDIUM 6.1DOWNGRADE

CVE-2021-41930 is a medium-severity flaw (CVSS 6.1) affecting online covid vaccination scheduler system. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross site scripting (XSS) vulnerability in Sourcecodester Online Covid Vaccination Scheduler System v1 by oretnom23, allows attackers to execute arbitrary code via the lid parameter to /scheduler/addSchedule.php.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-79
Published	2022-01-24
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: online covid vaccination scheduler system project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-01-24 19:15 UTCPublished CVE record published
2026-06-17 04:09 UTCUpdated Record last modified

online covid vaccination scheduler system project online covid vaccination scheduler system DOWNGRADE

Affected: 1.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.0

1. Check installed version

apt-cache policy online-covid-vaccination-scheduler-system || rpm -q online-covid-vaccination-scheduler-system || online-covid-vaccination-scheduler-system --version

2. No fixed release: DOWNGRADE to a release before 1.0 (Debian / Ubuntu)

apt-cache madison online-covid-vaccination-scheduler-system sudo apt install online-covid-vaccination-scheduler-system=<VERSION_BEFORE_1.0> sudo apt-mark hold online-covid-vaccination-scheduler-system

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list online-covid-vaccination-scheduler-system sudo dnf downgrade online-covid-vaccination-scheduler-system-<VERSION_BEFORE_1.0> sudo dnf versionlock add online-covid-vaccination-scheduler-system

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-41930?

online covid vaccination scheduler system: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-41930 being exploited?

CVE-2021-41930 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-41930 affect?

CVE-2021-41930 affects online covid vaccination scheduler system. Severity is medium (CVSS 6.1). Cross site scripting (XSS) vulnerability in Sourcecodester Online Covid Vaccination Scheduler System v1 by oretnom23, allows attackers to execute arbitrary code via the lid parameter to /scheduler/addSchedule.php.

How urgent is CVE-2021-41930?

Priority 42/100. Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2021-37803 HIGH 8.1 DOWNGRADE An SQL Injection vulnerability exists in Sourcecodester Online Covid Vaccination Scheduler System 1.0 via the
CVE-2021-36622 CRITICAL 9.8 DOWNGRADE Sourcecodester Online Covid Vaccination Scheduler System 1.0 is affected vulnerable to Arbitrary File Upload
CVE-2021-36621 HIGH 8.1 DOWNGRADE Sourcecodester Online Covid Vaccination Scheduler System 1.0 is vulnerable to SQL Injection

References

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