How severe is CVE-2021-39340?

CVE-2021-39340 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-39340 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39340?

CVE-2021-39340 affects Bracketspace Notification. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39340?

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

When was CVE-2021-39340 published?

CVE-2021-39340 was published on 2021-11-01 and last updated on 2026-06-17.

CVE-2021-39340

CVE-2021-39340 is a medium-severity vulnerability in Bracketspace Notification with a CVSS 3.x base score of 4.8. 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 4.8)
CVSS v2: 2.1
EPSS exploit prediction: 1% (55th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Bracketspace Notification
Published: 2021-11-01
Last modified: 2026-06-17

Description

The Notification WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization via several parameters found in the ~/src/classes/Utils/Settings.php file which made it possible for attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 7.2.4. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.

Frequently asked questions

What is CVE-2021-39340?: The Notification WordPress plugin is vulnerable to Stored Cross-Site Scripting due to insufficient input validation and sanitization via several parameters found in the ~/src/classes/Utils/Settings.php file which made it possible for attackers with administrative user access to inject arbitrary web scripts, in versions up to and including 7.2.4. This affects multi-site installations where unfiltered_html is disabled for administrators, and sites where unfiltered_html is disabled.
How severe is CVE-2021-39340?: CVE-2021-39340 has a CVSS 3.x base score of 4.8, rated medium severity. It is exploitable over network with low attack complexity, requires high privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-39340 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39340?: CVE-2021-39340 affects Bracketspace Notification. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39340?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-39340 published?: CVE-2021-39340 was published on 2021-11-01 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:bracketspace:notification:*:*:*:*:*:wordpress:*:*

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