How severe is CVE-2021-33038?

CVE-2021-33038 has a CVSS 3.x base score of 7.5, 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 none, and availability none.

Is CVE-2021-33038 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33038?

CVE-2021-33038 primarily affects Hyperkitty Project Hyperkitty. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-33038?

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-2021-33038 published?

CVE-2021-33038 was published on 2021-05-26 and last updated on 2026-06-17.

CVE-2021-33038

CVE-2021-33038 is a high-severity vulnerability in Hyperkitty Project Hyperkitty with a CVSS 3.x base score of 7.5. 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-276.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-276
Affected product: Hyperkitty Project Hyperkitty
Published: 2021-05-26
Last modified: 2026-06-17

Description

An issue was discovered in management/commands/hyperkitty_import.py in HyperKitty through 1.3.4. When importing a private mailing list's archives, these archives are publicly visible for the duration of the import. For example, sensitive information might be available on the web for an hour during a large migration from Mailman 2 to Mailman 3.

Frequently asked questions

What is CVE-2021-33038?: An issue was discovered in management/commands/hyperkitty_import.py in HyperKitty through 1.3.4. When importing a private mailing list's archives, these archives are publicly visible for the duration of the import. For example, sensitive information might be available on the web for an hour during a large migration from Mailman 2 to Mailman 3.
How severe is CVE-2021-33038?: CVE-2021-33038 has a CVSS 3.x base score of 7.5, 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 none, and availability none.
Is CVE-2021-33038 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33038?: CVE-2021-33038 primarily affects Hyperkitty Project Hyperkitty. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-33038?: 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-2021-33038 published?: CVE-2021-33038 was published on 2021-05-26 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:hyperkitty_project:hyperkitty:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

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