The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the form response message post meta fields (e.g., 'text_subscribed', 'text_error') in all versions up to, and including, 4.12.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
CVE-2026-4561
MEDIUMPre-NVD 6.46.4—Trending — 3 sources updated this week
EchelonGraph scoreHIGH confidence
Score 6.4 from GitHub Security Advisory published 2026-08-22. a secondary CVSS source baseline 6.4; sources differ by 0.0.
Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
6.4EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.4Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 6.4
- EG Score
- 6.4(high)
- EG Risk
- 29(Track)EG Risk 29/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity64% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 24%
- KEV
- Not listed
Published
August 22, 2026
Last Modified
August 24, 2026
References (5)
- security@wordfencehttps://plugins.trac.wordpress.org/browser/mailchimp-for-wp/trunk/includes/forms/class-form-element.php#L116
- security@wordfencehttps://plugins.trac.wordpress.org/browser/mailchimp-for-wp/trunk/includes/forms/class-form-manager.php#L104
- security@wordfencehttps://plugins.trac.wordpress.org/browser/mailchimp-for-wp/trunk/includes/forms/class-form.php#L295
- security@wordfencehttps://plugins.trac.wordpress.org/changeset/3491781/
- security@wordfencehttps://www.wordfence.com/threat-intel/vulnerabilities/id/641b739d-f888-4327-b1c5-c95de39ee011?source=cve
Vendor Advisories for CVE-2026-4561(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 22× in last 7d / 25× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-30 02:57 UTCEG score recompute
- 2026-08-30 02:57 UTCGHSA enrichment
- 2026-08-30 01:22 UTCEPSS rescore
- 2026-08-29 01:00 UTCEG score recompute
- 2026-08-29 01:00 UTCGHSA enrichment
- 2026-08-28 21:41 UTCEPSS rescore
- 2026-08-27 22:42 UTCEG score recompute
- 2026-08-27 22:42 UTCGHSA enrichment
- 2026-08-27 14:25 UTCEPSS rescore
- 2026-08-26 20:46 UTCEG score recompute
- 2026-08-26 20:46 UTCGHSA enrichment
- 2026-08-26 14:46 UTCEPSS rescore
- 2026-08-25 18:43 UTCEG score recompute
- 2026-08-25 18:43 UTCGHSA enrichment
- 2026-08-25 13:49 UTCEPSS rescore
- 2026-08-24 16:47 UTCGHSA enrichment
- 2026-08-24 14:25 UTCEG score recompute
- 2026-08-24 14:24 UTCGHSA enrichment
- 2026-08-24 13:23 UTCEG score recompute
- 2026-08-24 13:23 UTCGHSA enrichment
- 2026-08-23 16:18 UTCEG score recompute
- 2026-08-23 16:18 UTCGHSA enrichment
- 2026-08-22 14:22 UTCEG score recompute
- 2026-08-22 13:36 UTCEG score recompute
- 2026-08-22 13:35 UTCMITRE cvelistV5first tracked
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-4561?
CVE-2026-4561 is a medium vulnerability published on August 22, 2026. The MC4WP: Mailchimp for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the form response message post meta fields (e.g., 'textsubscribed', 'texterror') in all versions up to, and including, 4.12.0 due to insufficient input sanitization and output escaping. This…
When was CVE-2026-4561 disclosed?
CVE-2026-4561 was first published in the National Vulnerability Database on August 22, 2026, with the most recent update on August 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4561 actively exploited?
CVE-2026-4561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 75.9% of all scored CVEs.
What is the CVSS score of CVE-2026-4561?
CVE-2026-4561 has a CVSS v3 base score of 6.4 (NVD).
How do I remediate CVE-2026-4561?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4561, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-4561
Is Your Infrastructure Affected by CVE-2026-4561?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.