CVE-2021-30149: Composr 10.0.36 allows upload and execution of PHP files.

This week

CRITICAL 9.8REMOTEDOWNGRADE

CVE-2021-30149 is a critical-severity flaw (CVSS 9.8) affecting composr. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Composr 10.0.36 allows upload and execution of PHP files.

Why this priority

Critical severity
EPSS top 4%: very likely to be exploited
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	10.1% (top 4%)
CISA exploited list	No
Weakness	CWE-434
Published	2021-04-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: ocproducts

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

Am I affected?

Timeline

2021-04-06 06:15 UTCPublished CVE record published
2026-06-17 03:49 UTCUpdated Record last modified

ocproducts composr DOWNGRADE

Affected: 10.0.36

Fixed in: no fixed release known

Safe to downgrade to: a release before 10.0.36

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 10.0.36 (Debian / Ubuntu)

apt-cache madison composr sudo apt install composr=<VERSION_BEFORE_10.0.36> sudo apt-mark hold composr

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

dnf --showduplicates list composr sudo dnf downgrade composr-<VERSION_BEFORE_10.0.36> sudo dnf versionlock add composr

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: Composr 10.0.36 - Remote Code Execution

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-2021-30149?

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

Is CVE-2021-30149 being exploited?

CVE-2021-30149 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-2021-30149 affect?

CVE-2021-30149 affects composr. Severity is critical (CVSS 9.8). Composr 10.0.36 allows upload and execution of PHP files.

How urgent is CVE-2021-30149?

Priority 68/100. Critical severity; EPSS top 4%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

PHP vulnerabilities

Related CVEs

CVE-2021-46360 HIGH 8.8 UPGRADE Authenticated remote code execution (RCE) in Composr-CMS 10.0.39 and earlier allows remote attackers to execut
CVE-2021-30150 MEDIUM 6.1 DOWNGRADE Composr 10.0.36 allows XSS in an XML script.

References

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