CVE-2021-44521

CVE-2021-44521 is a critical-severity vulnerability in Apache Cassandra with a CVSS 3.x base score of 9.1. Its EPSS exploit-prediction score of 55% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-732.

Key facts

Description

When running Apache Cassandra with the following configuration: enable_user_defined_functions: true enable_scripted_user_defined_functions: true enable_user_defined_functions_threads: false it is possible for an attacker to execute arbitrary code on the host. The attacker would need to have enough permissions to create user defined functions in the cluster to be able to exploit this. Note that this configuration is documented as unsafe, and will continue to be considered unsafe after this CVE.

Frequently asked questions

What is CVE-2021-44521?
When running Apache Cassandra with the following configuration: enable_user_defined_functions: true enable_scripted_user_defined_functions: true enable_user_defined_functions_threads: false it is possible for an attacker to execute arbitrary code on the host. The attacker would need to have enough permissions to create user defined functions in the cluster to be able to exploit this. Note that this configuration is documented as unsafe, and will continue to be considered unsafe after this CVE.
How severe is CVE-2021-44521?
CVE-2021-44521 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-44521 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 55% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-44521?
CVE-2021-44521 affects Apache Cassandra. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-44521?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-44521 published?
CVE-2021-44521 was published on 2022-02-11 and last updated on 2026-06-17.

References

Affected products (1)

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