CVE-2021-33191

Name: CVE-2021-33191
Creator: NVD / NIST
Published: 2021-08-24T12:15:07.307+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 4.02%

Last modified Jun 17, 2026

CVE-2021-33191 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. From Apache NiFi MiNiFi C++ version 0.5.0 the c2 protocol implements an "agent-update" command which was designed to patch the application binary. This "patching" command defaults to calling a trusted binary, but might be modified to an arbitrary value through a "c2-update" command. EPSS estimates a 4.02% chance of exploitation in the next 30 days.

Description

From Apache NiFi MiNiFi C++ version 0.5.0 the c2 protocol implements an "agent-update" command which was designed to patch the application binary. This "patching" command defaults to calling a trusted binary, but might be modified to an arbitrary value through a "c2-update" command. Said command is then executed using the same privileges as the application binary. This was addressed in version 0.10.0

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

4.02%

89.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Apache	Nifi Minifi C\+\+	>= 0.5.0, < 0.10.0

References

http://www.openwall.com/lists/oss-security/2021/08/24/1Mailing List, Third Party Advisory
https://lists.apache.org/thread.html/r6f27a2454f5f67dbe4e21c8eb1db537b01863a0bc3758f28aa60f032%40%3Cannounce.apache.org%3E
https://www.openwall.com/lists/oss-security/2021/08/24/1Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/08/24/1Mailing List, Third Party Advisory
https://lists.apache.org/thread.html/r6f27a2454f5f67dbe4e21c8eb1db537b01863a0bc3758f28aa60f032%40%3Cannounce.apache.org%3E
https://www.openwall.com/lists/oss-security/2021/08/24/1Mailing List, Third Party Advisory

Timeline

Published: Aug 24, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33191?

How severe is CVE-2021-33191?

CVE-2021-33191 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 4.02% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33191?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33191?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST