How severe is CVE-2021-39341?

CVE-2021-39341 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2021-39341 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 23% (98th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39341?

CVE-2021-39341 affects Optinmonster. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39341?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-39341 published?

CVE-2021-39341 was published on 2021-11-01 and last updated on 2026-06-17.

CVE-2021-39341

CVE-2021-39341 is a high-severity vulnerability in Optinmonster with a CVSS 3.x base score of 8.2. Its EPSS exploit-prediction score of 23% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-863.

Key facts

Severity: High (CVSS 3.x base score 8.2)
CVSS v2: 6.4
EPSS exploit prediction: 23% (98th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-863
Affected product: Optinmonster
Published: 2021-11-01
Last modified: 2026-06-17

Description

The OptinMonster WordPress plugin is vulnerable to sensitive information disclosure and unauthorized setting updates due to insufficient authorization validation via the logged_in_or_has_api_key function in the ~/OMAPI/RestApi.php file that can used to exploit inject malicious web scripts on sites with the plugin installed. This affects versions up to, and including, 2.6.4.

Frequently asked questions

What is CVE-2021-39341?: The OptinMonster WordPress plugin is vulnerable to sensitive information disclosure and unauthorized setting updates due to insufficient authorization validation via the logged_in_or_has_api_key function in the ~/OMAPI/RestApi.php file that can used to exploit inject malicious web scripts on sites with the plugin installed. This affects versions up to, and including, 2.6.4.
How severe is CVE-2021-39341?: CVE-2021-39341 has a CVSS 3.x base score of 8.2, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2021-39341 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 23% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39341?: CVE-2021-39341 affects Optinmonster. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39341?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39341 published?: CVE-2021-39341 was published on 2021-11-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:optinmonster:optinmonster:*:*:*:*:*:wordpress:*:*

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