How severe is CVE-2021-4244?

CVE-2021-4244 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2021-4244?

CVE-2021-4244 affects the following packages: yikesinc/yikes-inc-easy-mailchimp-extender (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2021-4244?

Update yikesinc/yikes-inc-easy-mailchimp-extender to 6.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-4244 is resolved across your whole dependency graph.

How do I detect CVE-2021-4244 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yikesinc/yikes-inc-easy-mailchimp-extender, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2021-4244 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2021-4244 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-4244 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-4244?

CVE-2021-4244 has an EPSS (Exploit Prediction Scoring System) score of 0.6%, placing it in the 48th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-4244?

CVE-2021-4244 is classified as CWE-707 (CWE-707), Cross-site Scripting (XSS) (CWE-79). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2021-4244 published, and has it been updated?

CVE-2021-4244 was published on December 12, 2022 and was last updated on October 20, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

MEDIUM severity

CVE-2021-4244 — yikes-inc-easy-mailchimp-…

MEDIUMFix: EvanHerman/yikes-inc-easy-mailchimp-extender@3662c65

CVE-2021-4244 is a medium-severity (CVSS 6.1) CWE-707 vulnerability in yikesinc/yikes-inc-easy-mailchimp-extender. A fix is available for yikesinc/yikes-inc-easy-mailchimp-extender — see the affected versions and patch details below.

yikes-inc-easy-mailchimp-extender Cross-site Scripting vulnerability

Also known asGHSA-837v-6vgx-jqcc

Published

Dec 12, 2022

Updated

Oct 20, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2021-4244.

EPSS Exploitation Probability

via FIRST.org ↗

0.6%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs48th percentile — riskier than 48% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐘yikesinc/yikes-inc-easy-mailchimp-extender

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

A vulnerability classified as problematic has been found in yikes-inc-easy-mailchimp-extender Plugin up to 6.8.5. This affects an unknown part of the file admin/partials/ajax/add_field_to_form.php. The manipulation of the argument field_name/merge_tag/field_type/list_id leads to cross site scripting. It is possible to initiate the attack remotely. Upgrading to version 6.8.6 is able to address this issue. The name of the patch is 3662c6593aa1bb4286781214891d26de2e947695. It is recommended to upgrade the affected component. The associated identifier of this vulnerability is VDB-215307.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`yikesinc/yikes-inc-easy-mailchimp-extender`	all versions	6.8.6`composer require yikesinc/yikes-inc-easy-mailchimp-extender:^6.8.6`

Affected Products

1 product · 1 configurations

Application

easy forms for mailchimpyikesplugins

< 6.8.6

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yikesinc/yikes-inc-easy-mailchimp-extender, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update yikesinc/yikes-inc-easy-mailchimp-extender to 6.8.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-4244 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2021-4244 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-707CWE-707 CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Dec 12, 2022

Last updated

Oct 20, 2026

Identifiers

CVE-2021-4244

GHSA-837v-6vgx-jqcc

References

Advisorygithub.com · 6.8.6 Advisoryvuldb.com Advisorynvd.nist.gov · CVE 2021 4244 Fixgithub.com · 3662c6593aa1bb4286781214891d26de2e947695 Fixgithub.com Packagegithub.com · yikes inc easy mailchimp extender

Related vulnerabilities

Same weakness: CWE-707

This CVE is medium severity; 3 of 3 other CVEs with CWE-707 are rated as high or higher (top: high).

CVE-2022-4638CVE-2022-4396CVE-2022-3801Browse all CWE-707

Same weakness: CWE-79

This CVE is medium severity; 5 of 5 other CVEs with CWE-79 are rated as high or higher (top: critical).

CVE-2026-88986CVE-2026-63197CVE-2026-55649CVE-2026-113787CVE-2026-44267Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 20, 2026