How severe is CVE-2021-43331?

CVE-2021-43331 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-43331 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43331?

CVE-2021-43331 primarily affects Gnu Mailman. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-43331?

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

When was CVE-2021-43331 published?

CVE-2021-43331 was published on 2021-11-12 and last updated on 2026-06-17.

CVE-2021-43331

CVE-2021-43331 is a medium-severity vulnerability in Gnu Mailman with a CVSS 3.x base score of 6.1. 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 6.1)
CVSS v2: 4.3
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-79
Affected product: Gnu Mailman
Published: 2021-11-12
Last modified: 2026-06-17

Description

In GNU Mailman before 2.1.36, a crafted URL to the Cgi/options.py user options page can execute arbitrary JavaScript for XSS.

Frequently asked questions

What is CVE-2021-43331?: In GNU Mailman before 2.1.36, a crafted URL to the Cgi/options.py user options page can execute arbitrary JavaScript for XSS.
How severe is CVE-2021-43331?: CVE-2021-43331 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-43331 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43331?: CVE-2021-43331 primarily affects Gnu Mailman. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-43331?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-43331 published?: CVE-2021-43331 was published on 2021-11-12 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:gnu:mailman:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

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