CVE-2021-43686: nZEDb v0.4.20 is affected by a Cross Site Scripting (XSS) vulnerability in www/pages/api.php

Routine

MEDIUM 6.1DOWNGRADE

CVE-2021-43686 is a medium-severity flaw (CVSS 6.1) affecting nzedb. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

nZEDb v0.4.20 is affected by a Cross Site Scripting (XSS) vulnerability in www/pages/api.php. The exit function will terminate the script and print the message which has the input $_GET['t'].

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	0.6% (top 49%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-12-02
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nzedb project

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

Am I affected?

Timeline

2021-12-02 13:15 UTCPublished CVE record published
2026-06-17 04:11 UTCUpdated Record last modified

nzedb project nzedb DOWNGRADE

Affected: 0.4.20

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.4.20

1. Check installed version

apt-cache policy nzedb || rpm -q nzedb || nzedb --version

2. No fixed release: DOWNGRADE to a release before 0.4.20 (Debian / Ubuntu)

apt-cache madison nzedb sudo apt install nzedb=<VERSION_BEFORE_0.4.20> sudo apt-mark hold nzedb

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

dnf --showduplicates list nzedb sudo dnf downgrade nzedb-<VERSION_BEFORE_0.4.20> sudo dnf versionlock add nzedb

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-2021-43686?

nzedb: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-43686 being exploited?

CVE-2021-43686 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-2021-43686 affect?

CVE-2021-43686 affects nzedb. Severity is medium (CVSS 6.1). nZEDb v0.4.20 is affected by a Cross Site Scripting (XSS) vulnerability in www/pages/api.php. The exit function will terminate the script and print the message which has the input $_GET['t'].

How urgent is CVE-2021-43686?

Priority 39/100. Public exploit reference

Software pages

PHP vulnerabilities

References

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