CVE-2020-4043: phpMussel from versions 1.0.0 and less than 1.6.0 has an unserialization vulnerability in PHP's phar wrapper

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HIGH 7.7UPGRADE

CVE-2020-4043 is a high-severity flaw (CVSS 7.7) affecting phpmussel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

phpMussel from versions 1.0.0 and less than 1.6.0 has an unserialization vulnerability in PHP's phar wrapper. Uploading a specially crafted file to an affected version allows arbitrary code execution (discovered, tested, and confirmed by myself), so the risk factor should be regarded as very high. Newer phpMussel versions don't use PHP's phar wrapper, and are therefore unaffected. This has been fixed in version 1.6.0.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.7 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	2.6% (top 15%)
CISA exploited list	No
Weakness	CWE-502
Published	2020-06-10
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: phpmussel project

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

Am I affected?

Timeline

2020-06-10 20:15 UTCPublished CVE record published
2026-06-17 03:19 UTCUpdated Record last modified

phpmussel project phpmussel UPGRADE

Affected: >= 1.0.0 and < 1.6.0

Fixed in: 1.6.0

Safe to downgrade to: a release before 1.0.0

1. Check installed version

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

2. UPGRADE to 1.6.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade phpmussel

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade phpmussel

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.0.0 (Debian / Ubuntu)

apt-cache madison phpmussel sudo apt install phpmussel=<VERSION_BEFORE_1.0.0> sudo apt-mark hold phpmussel

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list phpmussel sudo dnf downgrade phpmussel-<VERSION_BEFORE_1.0.0> sudo dnf versionlock add phpmussel

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-2020-4043?

phpmussel: upgrade to 1.6.0. Exact commands for each OS are on this page.

Is CVE-2020-4043 being exploited?

CVE-2020-4043 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-2020-4043 affect?

CVE-2020-4043 affects phpmussel. Severity is high (CVSS 7.7). phpMussel from versions 1.0.0 and less than 1.6.0 has an unserialization vulnerability in PHP's phar wrapper. Uploading a specially crafted file to an affected version allows arbitrary code execution (discovered, tested, and confirmed by my

How urgent is CVE-2020-4043?

Priority 48/100. High severity

Software pages

PHP vulnerabilities

References

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