CVE-2021-44521

Q: How do I fix CVE-2021-44521?

Upgrade cassandra to 4.0.2 or later.

Q: Is CVE-2021-44521 being actively exploited?

Not that we know of. CVE-2021-44521 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 55.0% is the estimated probability that it will be exploited in the next 30 days. That is higher than 99% of all scored CVEs.

Q: How severe is CVE-2021-44521?

CVE-2021-44521 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

Q: What does CVE-2021-44521 affect?

Published advisories record a fix for cassandra (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

CRITICALEPSS 99th pctl

9.1

CVSS v3

NVD

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.

CWE-94Code Injection CWE-732Incorrect Permission Assignment for Critical Resource

How to fix

Remediation Available

cassandraNVD

Affected:>= 4.0.0, < 4.0.2Fixed in:4.0.2CVE-2021-44521derived from NVD

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredHigh

User InteractionNone

ScopeChanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploit Intelligence

55.01%probability of exploitation in 30 days

99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

Exploit1

jfrog.com

Vendor Advisory1

lists.apache.org

Third-Party Advisory2

Related Vulnerabilities

Other CWE-94 (Code Injection) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2017-9841	Critical	9.8	100%	KEV	Fix
CVE-2015-1635	Critical	9.8	100%	KEV	-
CVE-2025-3248	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2022-22954	Critical	9.8	100%	KEV + Ransom	-
CVE-2021-22204	Medium	6.8	100%	KEV	Fix
CVE-2012-0158	High	8.8	100%	KEV	-

Common questions

How do I fix CVE-2021-44521?

Upgrade cassandra to 4.0.2 or later.

Is CVE-2021-44521 being actively exploited?

Not that we know of. CVE-2021-44521 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 55.0% is the estimated probability that it will be exploited in the next 30 days. That is higher than 99% of all scored CVEs.

How severe is CVE-2021-44521?

CVE-2021-44521 has a CVSS v3 base score of 9.1, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2021-44521 affect?

Published advisories record a fix for cassandra (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.