MC4WP: Mailchimp for WordPress < 4.15.0 - Unauthenticated Arbitrary Shortcode Execution via Dynamic Content Tag
- Exploited
- No known exploitation
- Fix
- Fixed in 4.15.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 4.15.0.
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.18% · 7th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 22/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
The MC4WP: Mailchimp for WordPress plugin, before its fixed release, lets a remote visitor without logging in run registered WordPress shortcodes with attacker-chosen attributes. This only happens on sites where the owner added a request-derived dynamic tag to a form embedded with the block rather than the classic shortcode.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
The MC4WP: Mailchimp for WordPress WordPress plugin before 4.15.0 does not prevent request-derived values in its dynamic content tags from being processed as shortcodes when a form is embedded with its block, allowing unauthenticated visitors to execute arbitrary registered shortcodes with attacker-chosen attributes. This requires the site owner to have added a request-derived tag to the form content and to embed the form with the block rather than the classic shortcode.
cve.now Index
- Exploitation0/40No signal
- Exposure17/25No login or user action needed per the CVSS vector, reachable over the network without a login · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity4.8/10CVSS 4.8
- No patch0/5No signal
What would change the score
- Would score about 67 if added to CISA KEV
- Would score about 62 if CISA's SSVC rates exploitation active
- Would score about 27 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 4.15.0.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Unknown MC4WP: Mailchimp for WordPress
fixed in 4.15.0
Evidence 1
- Exploit
Corrections
None so far.
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Questions about CVE-2026-118166
Is CVE-2026-118166 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-118166?
MC4WP: Mailchimp for WordPress: before 4.15.0.Source: cve.now feed data
How do I fix CVE-2026-118166?
Upgrade to a fixed version: 4.15.0.Source: cve.now feed data