CVE-2021-39427: Cross site scripting vulnerability in 188Jianzhan 2.10 allows attackers to execute arbitrary code via the user

Routine

MEDIUM 5.4DOWNGRADE

CVE-2021-39427 is a medium-severity flaw (CVSS 5.4) affecting 188jianzhan. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross site scripting vulnerability in 188Jianzhan 2.10 allows attackers to execute arbitrary code via the username parameter to /admin/reg.php.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.5% (top 59%)
CISA exploited list	No
Weakness	CWE-79
Published	2022-12-15
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: vtimecn

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

Am I affected?

Timeline

2022-12-15 19:15 UTCPublished CVE record published
2026-06-17 04:03 UTCUpdated Record last modified

vtimecn 188jianzhan DOWNGRADE

Affected: 2.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.10

1. Check installed version

apt-cache policy 188jianzhan || rpm -q 188jianzhan || 188jianzhan --version

2. No fixed release: DOWNGRADE to a release before 2.10 (Debian / Ubuntu)

apt-cache madison 188jianzhan sudo apt install 188jianzhan=<VERSION_BEFORE_2.10> sudo apt-mark hold 188jianzhan

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

dnf --showduplicates list 188jianzhan sudo dnf downgrade 188jianzhan-<VERSION_BEFORE_2.10> sudo dnf versionlock add 188jianzhan

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-2021-39427?

188jianzhan: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-39427 being exploited?

CVE-2021-39427 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-2021-39427 affect?

CVE-2021-39427 affects 188jianzhan. Severity is medium (CVSS 5.4). Cross site scripting vulnerability in 188Jianzhan 2.10 allows attackers to execute arbitrary code via the username parameter to /admin/reg.php.

How urgent is CVE-2021-39427?

Priority 34/100. Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2020-23685 CRITICAL 9.8 DOWNGRADE SQL Injection vulnerability in 188Jianzhan v2.1.0, allows attackers to execute arbitrary code and gain escalat

References

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