CVE-2021-36654: CMSuno 1.7 is vulnerable to an authenticated stored cross site scripting in modifying the filename parameter (

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MEDIUM 5.4DOWNGRADE

CVE-2021-36654 is a medium-severity flaw (CVSS 5.4) affecting cmsuno. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

CMSuno 1.7 is vulnerable to an authenticated stored cross site scripting in modifying the filename parameter (tgo) while updating the theme.

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	1.9% (top 20%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-08-03
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: cmsuno project

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

Am I affected?

Timeline

2021-08-03 18:15 UTCPublished CVE record published
2026-06-17 03:58 UTCUpdated Record last modified

cmsuno project cmsuno DOWNGRADE

Affected: 1.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.7

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.7 (Debian / Ubuntu)

apt-cache madison cmsuno sudo apt install cmsuno=<VERSION_BEFORE_1.7> sudo apt-mark hold cmsuno

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

dnf --showduplicates list cmsuno sudo dnf downgrade cmsuno-<VERSION_BEFORE_1.7> sudo dnf versionlock add cmsuno

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: CMSuno 1.7 - 'tgo' Stored Cross-Site Scripting (XSS) (Authenticated)

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-2021-36654?

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

Is CVE-2021-36654 being exploited?

CVE-2021-36654 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-2021-36654 affect?

CVE-2021-36654 affects cmsuno. Severity is medium (CVSS 5.4). CMSuno 1.7 is vulnerable to an authenticated stored cross site scripting in modifying the filename parameter (tgo) while updating the theme.

How urgent is CVE-2021-36654?

Priority 44/100. Public exploit reference

Related CVEs

CVE-2021-40889 CRITICAL 9.8 DOWNGRADE CMSUno version 1.7.2 is affected by a PHP code execution vulnerability
CVE-2020-25557 HIGH 8.8 DOWNGRADE In CMSuno 1.6.2, an attacker can inject malicious PHP code as a "username" while changing his/her username & p
CVE-2020-25538 HIGH 8.8 DOWNGRADE An authenticated attacker can inject malicious code into "lang" parameter in /uno/central.php file in CMSuno 1
CVE-2020-15600 MEDIUM 6.5 UPGRADE An issue was discovered in CMSUno before 1.6.1

References

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