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Vulnerabilities

Vulnerability · CVE-2026-109515

The MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc.

Published Oct 16, 2026 · catalog updated Oct 16, 2026 · The MailOptin – Popup,

Patch now

CVE-2026-109515 is in the CISA known-exploited catalog. Confirm The MailOptin – Popup, against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
0.44%
Remediation
Remediation guidance
Affected products
vendor mailoptin mailoptin

The MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc. plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.78.6 This is due to the endpoint accepting an attacker-supplied parameter without any allow-list validation on destination keys, allowing the attacker-controlled mapping to override the administrator's saved mapping and pass arbitrary column names — including and — directly into via the function. This makes it possible for unauthenticated attackers to force into UPDATE mode on any existing account by supplying a target user's numeric , overwrite that account's password with a pre-hashed value of their choosing, and thereby take over any WordPress user account — including administrators — leading to full site compromise. Exploitation requires that a WordPress User Registration opt-in form is published somewhere on the site, though the form's UUID is visible in page source and no authentication, nonce, or capability check is required to reach the vulnerable endpoint.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

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  • vendor mailoptin mailoptinversion unspecified

How to fix CVE-2026-109515

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2026-109515 is in the CISA known-exploited catalog. Confirm The MailOptin – Popup, against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-269: Improper Privilege Management. EPSS 0.44%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

WordPress security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 16, 2026 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  2. Oct 16, 2026 · NIST NVD

    Detected

    The MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc. plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.78.6 This is due to the endpoint accepting an attacker-supplied parameter without any allow-list validation on destination keys, allowing the attacker-controlled mapping to override the administrator's saved

Sources

  • CVE.orgVulnerability recordCVE-2026-109515

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-109515

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-2026-109515

    The MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc. plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.78.6 This is due to the endpoint accepting an attacker-supplie

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2026-109515

    The MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc. plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.78.6 This is due to the endpoint accepting an attacker-supplied parameter without any al

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.