CVE-2021-44521
Criticalcassandra: RCE for scripted UDFs
Published Feb 17, 2022 · Updated Sep 8, 2026 · Also known as BIT-cassandra-2021-44521, GHSA-8ffc-79xg-29w8
Key Facts
Patch immediately- CVE-2021-44521 is a critical-severity vulnerability (CVSS 9.1 v3.1) affecting Cassandra (Apache), druid (chainguard), org.apache.cassandra:cassandra-all (maven).
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 58% probability of exploitation in the next 30 days.
- Fixed versions are available, including Cassandra 3.0.26, Cassandra 3.11.12, Cassandra 4.0.2.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
9.1
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
58%
Higher than 99.0% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
Get the full CVE-2021-44521 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Affected Products
10 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| CassandraApache | >= 3.0.0 | 3.0.26 |
| druidchainguard | See advisory | 35.0.1-r1 |
| org.apache.cassandra:cassandra-allmaven | See advisory | 4.0.2 |
Patched Releases
Cassandra
3.0.26, 3.11.12, 4.0.2, unspecified, 3.11.12-1.ph1, 3.11.12-1.ph2, 3.11.12-1.ph3, 4.0.3-1.ph4
druid
35.0.1-r1
org.apache.cassandra:cassandra-all
3.0.26, 3.11.12, 4.0.2
Timeline
Publicly disclosed
Feb 17, 2022
Last updated
Sep 8, 2026
Weakness Type
- CWE-94 Improper Control of Generation of Code ('Code Injection')
- CWE-732 Incorrect Permission Assignment for Critical Resource
References
- advisoryGHSA advisory
- advisoryhttps://lists.apache.org/thread/y4nb9s4co34j8hdfmrshyl09lokm7356
- advisoryhttps://nvd.nist.gov/vuln/detail/CVE-2021-44521
- advisoryhttps://securityaffairs.co/
- advisoryhttps://securityaffairs.co/wordpress
FAQ
Common Questions.
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.
Affected: Cassandra (Apache) versions >= 3.0.0; druid (chainguard); org.apache.cassandra:cassandra-all (maven). The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Cassandra 3.0.26, Cassandra 3.11.12, Cassandra 4.0.2.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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