CVE-2021-40889: CMSUno version 1.7.2 is affected by a PHP code execution vulnerability

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-40889 is a critical-severity flaw (CVSS 9.8) affecting cmsuno. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

CMSUno version 1.7.2 is affected by a PHP code execution vulnerability. sauvePass action in {webroot}/uno/central.php file calls to file_put_contents() function to write username in password.php file when a user successfully changed their password. The attacker can inject malicious PHP code into password.php and then use the login function to execute code.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.8% (top 21%)
CISA exploited list	No
Weakness	CWE-94
Published	2021-10-11
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

2021-10-11 10:15 UTCPublished CVE record published
2026-06-17 04:07 UTCUpdated Record last modified

cmsuno project cmsuno DOWNGRADE

Affected: 1.7.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.7.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.7.2 (Debian / Ubuntu)

apt-cache madison cmsuno sudo apt install cmsuno=<VERSION_BEFORE_1.7.2> sudo apt-mark hold cmsuno

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

dnf --showduplicates list cmsuno sudo dnf downgrade cmsuno-<VERSION_BEFORE_1.7.2> 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.

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-2021-40889?

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

Is CVE-2021-40889 being exploited?

CVE-2021-40889 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-2021-40889 affect?

CVE-2021-40889 affects cmsuno. Severity is critical (CVSS 9.8). CMSUno version 1.7.2 is affected by a PHP code execution vulnerability. sauvePass action in {webroot}/uno/central.php file calls to file_put_contents() function to write username in password.php file when a user successfully changed their p

How urgent is CVE-2021-40889?

Priority 64/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2021-36654 MEDIUM 5.4 DOWNGRADE CMSuno 1.7 is vulnerable to an authenticated stored cross site scripting in modifying the filename parameter (
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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