CVE-2020-25557: In CMSuno 1.6.2, an attacker can inject malicious PHP code as a "username" while changing his/her username & p

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HIGH 8.8DOWNGRADE

CVE-2020-25557 is a high-severity flaw (CVSS 8.8) affecting cmsuno. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In CMSuno 1.6.2, an attacker can inject malicious PHP code as a "username" while changing his/her username & password. After that, when attacker logs in to the application, attacker's code will be run. As a result of this vulnerability, authenticated user can run command on the server.

Why this priority

High severity
EPSS top 4%: very likely to be exploited
Public exploit reference

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

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	10.0% (top 4%)
CISA exploited list	No
Weakness	CWE-94
Published	2020-11-13
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

2020-11-13 16:15 UTCPublished CVE record published
2026-06-17 03:06 UTCUpdated Record last modified

cmsuno project cmsuno DOWNGRADE

Affected: 1.6.2

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.6.2

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 1.6.2 (Debian / Ubuntu)

apt-cache madison cmsuno sudo apt install cmsuno=<VERSION_BEFORE_1.6.2> sudo apt-mark hold cmsuno

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

dnf --showduplicates list cmsuno sudo dnf downgrade cmsuno-<VERSION_BEFORE_1.6.2> 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.

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 1.6.2 - 'lang' Remote Code Execution (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-2020-25557?

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

Is CVE-2020-25557 being exploited?

CVE-2020-25557 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-2020-25557 affect?

CVE-2020-25557 affects cmsuno. Severity is high (CVSS 8.8). In CMSuno 1.6.2, an attacker can inject malicious PHP code as a "username" while changing his/her username & password. After that, when attacker logs in to the application, attacker's code will be run. As a result of this vulnerability, aut

How urgent is CVE-2020-25557?

Priority 60/100. High severity; EPSS top 4%: very likely to be exploited; Public exploit reference

Software pages

PHP vulnerabilities

Related CVEs

CVE-2021-40889 CRITICAL 9.8 DOWNGRADE CMSUno version 1.7.2 is affected by a PHP code execution vulnerability
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-2020-25538 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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