CVE-2021-33851: A cross-site scripting (XSS) attack can cause arbitrary code (JavaScript) to run in a user's browser and can u

Q: How do I fix CVE-2021-33851?

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

Q: Is CVE-2021-33851 being exploited?

CVE-2021-33851 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-2021-33851 affect?

CVE-2021-33851 affects customize login image. Severity is medium (CVSS 5.4). A cross-site scripting (XSS) attack can cause arbitrary code (JavaScript) to run in a user's browser and can use an application as the vehicle for the attack. The XSS payload given in the "Custom logo link" executes whenever the user opens

Q: How urgent is CVE-2021-33851?

Priority 42/100. Public exploit reference

This month

MEDIUM 5.4DOWNGRADE

CVE-2021-33851 is a medium-severity flaw (CVSS 5.4) affecting customize login image. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A cross-site scripting (XSS) attack can cause arbitrary code (JavaScript) to run in a user's browser and can use an application as the vehicle for the attack. The XSS payload given in the "Custom logo link" executes whenever the user opens the Settings Page of the "Customize Login Image" Plugin.

Why this priority

Public exploit reference

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

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-79
Published	2022-03-10
Last modified	2026-06-17

Publisher (CNA): Cyber Security Works Pvt. Ltd. · Vendor: apasionados

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

Am I affected?

Timeline

2022-03-10 17:42 UTCPublished CVE record published
2026-06-17 03:55 UTCUpdated Record last modified

apasionados customize login image DOWNGRADE

Affected: 3.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.4

1. Check installed version

apt-cache policy customize-login-image || rpm -q customize-login-image || customize-login-image --version

2. No fixed release: DOWNGRADE to a release before 3.4 (Debian / Ubuntu)

apt-cache madison customize-login-image sudo apt install customize-login-image=<VERSION_BEFORE_3.4> sudo apt-mark hold customize-login-image

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

dnf --showduplicates list customize-login-image sudo dnf downgrade customize-login-image-<VERSION_BEFORE_3.4> sudo dnf versionlock add customize-login-image

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.

Nuclei scan template: WordPress Customize Login Image <3.5.3 - Cross-Site Scripting

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-2021-33851?

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

Is CVE-2021-33851 being exploited?

CVE-2021-33851 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-2021-33851 affect?

CVE-2021-33851 affects customize login image. Severity is medium (CVSS 5.4). A cross-site scripting (XSS) attack can cause arbitrary code (JavaScript) to run in a user's browser and can use an application as the vehicle for the attack. The XSS payload given in the "Custom logo link" executes whenever the user opens

How urgent is CVE-2021-33851?

Priority 42/100. Public exploit reference

References

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