CVE-2020-21643: Cross Site Scripting (XSS) vulnerability in HongCMS 3.0 allows attackers to run arbitrary code via the callbac

Routine

MEDIUM 6.1DOWNGRADE

CVE-2020-21643 is a medium-severity flaw (CVSS 6.1) affecting hongcms. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross Site Scripting (XSS) vulnerability in HongCMS 3.0 allows attackers to run arbitrary code via the callback parameter to /ajax/myshop.

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	0.4% (top 65%)
CISA exploited list	No
Weakness	CWE-79
Published	2023-04-28
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: hongcms project

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

Am I affected?

Timeline

2023-04-28 20:15 UTCPublished CVE record published
2026-06-17 03:03 UTCUpdated Record last modified

hongcms project hongcms DOWNGRADE

Affected: 3.0.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)

apt-cache madison hongcms sudo apt install hongcms=<VERSION_BEFORE_3.0.0> sudo apt-mark hold hongcms

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

dnf --showduplicates list hongcms sudo dnf downgrade hongcms-<VERSION_BEFORE_3.0.0> sudo dnf versionlock add hongcms

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-2020-21643?

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

Is CVE-2020-21643 being exploited?

CVE-2020-21643 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-2020-21643 affect?

CVE-2020-21643 affects hongcms. Severity is medium (CVSS 6.1). Cross Site Scripting (XSS) vulnerability in HongCMS 3.0 allows attackers to run arbitrary code via the callback parameter to /ajax/myshop.

How urgent is CVE-2020-21643?

Priority 35/100. Public exploit reference

Related CVEs

CVE-2022-32412 HIGH 7.2 DOWNGRADE An issue in the /template/edit component of HongCMS v3.0 allows attackers to getshell.
CVE-2022-32411 HIGH 7.2 DOWNGRADE An issue in the languages config file of HongCMS v3.0 allows attackers to getshell.
CVE-2020-21252 HIGH 8.8 DOWNGRADE Cross Site Request Forgery vulnerability in Neeke HongCMS 3.0.0 allows a remote attacker to execute arbitrary

References

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