How severe is CVE-2021-40377?

CVE-2021-40377 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-40377 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40377?

CVE-2021-40377 affects Smartertools Smartermail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-40377?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-40377 published?

CVE-2021-40377 was published on 2021-09-08 and last updated on 2026-06-17.

CVE-2021-40377

CVE-2021-40377 is a medium-severity vulnerability in Smartertools Smartermail with a CVSS 3.x base score of 5.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Smartertools Smartermail
Published: 2021-09-08
Last modified: 2026-06-17

Description

SmarterTools SmarterMail 16.x before build 7866 has stored XSS. The application fails to sanitize email content, thus allowing one to inject HTML and/or JavaScript into a page that will then be processed and stored by the application.

Frequently asked questions

What is CVE-2021-40377?: SmarterTools SmarterMail 16.x before build 7866 has stored XSS. The application fails to sanitize email content, thus allowing one to inject HTML and/or JavaScript into a page that will then be processed and stored by the application.
How severe is CVE-2021-40377?: CVE-2021-40377 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-40377 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40377?: CVE-2021-40377 affects Smartertools Smartermail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-40377?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-40377 published?: CVE-2021-40377 was published on 2021-09-08 and last updated on 2026-06-17.

References

https://www.smartertools.com/smartermail/release-notes/current

Affected products (1)

cpe:2.3:a:smartertools:smartermail:*:*:*:*:*:*:*:*

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