CVE-2016-4566: Cross-site scripting (XSS) vulnerability in plupload.flash.swf in Plupload before 2.1.9, as used in WordPress

Q: How do I fix CVE-2016-4566?

wordpress: upgrade to newer than 4.5.1; plupload: upgrade to newer than 2.1.8. Exact commands for each OS are on this page.

Q: Is CVE-2016-4566 being exploited?

CVE-2016-4566 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2016-4566 affect?

CVE-2016-4566 affects wordpress, plupload. Severity is medium (CVSS 6.1). Cross-site scripting (XSS) vulnerability in plupload.flash.swf in Plupload before 2.1.9, as used in WordPress before 4.5.2, allows remote attackers to inject arbitrary web script or HTML via a Same-Origin Method Execution (SOME) attack.

Q: How urgent is CVE-2016-4566?

Priority 45/100. EPSS top 7%: very likely to be exploited

This month

MEDIUM 6.1UPGRADEUPGRADE

CVE-2016-4566 is a medium-severity flaw (CVSS 6.1) affecting wordpress, plupload. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-site scripting (XSS) vulnerability in plupload.flash.swf in Plupload before 2.1.9, as used in WordPress before 4.5.2, allows remote attackers to inject arbitrary web script or HTML via a Same-Origin Method Execution (SOME) attack.

Why this priority

EPSS top 7%: very likely to be exploited

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	6.0% (top 7%)
CISA exploited list	No
Weakness	CWE-79
Published	2016-05-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: plupload · wordpress

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

Am I affected?

Timeline

2016-05-22 01:59 UTCPublished CVE record published
2026-06-17 00:47 UTCUpdated Record last modified

wordpress wordpress UPGRADE

Affected: <= 4.5.1

Fixed in: newer than 4.5.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 4.5.1 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade wordpress

Note

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

plupload plupload UPGRADE

Affected: <= 2.1.8

Fixed in: newer than 2.1.8

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 2.1.8 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade plupload

Note

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

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-2016-4566?

wordpress: upgrade to newer than 4.5.1; plupload: upgrade to newer than 2.1.8. Exact commands for each OS are on this page.

Is CVE-2016-4566 being exploited?

CVE-2016-4566 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-2016-4566 affect?

CVE-2016-4566 affects wordpress, plupload. Severity is medium (CVSS 6.1). Cross-site scripting (XSS) vulnerability in plupload.flash.swf in Plupload before 2.1.9, as used in WordPress before 4.5.2, allows remote attackers to inject arbitrary web script or HTML via a Same-Origin Method Execution (SOME) attack.

How urgent is CVE-2016-4566?

Priority 45/100. EPSS top 7%: very likely to be exploited

Software pages

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References

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