How severe is CVE-2021-33176?

CVE-2021-33176 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 none, integrity none, and availability high.

Is CVE-2021-33176 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-33176?

CVE-2021-33176 affects Octavolabs Vernemq. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-33176?

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-2021-33176 published?

CVE-2021-33176 was published on 2021-06-08 and last updated on 2026-06-17.

CVE-2021-33176

CVE-2021-33176 is a high-severity vulnerability in Octavolabs Vernemq 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (62nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Octavolabs Vernemq
Published: 2021-06-08
Last modified: 2026-06-17

Description

VerneMQ MQTT Broker versions prior to 1.12.0 are vulnerable to a denial of service attack as a result of excessive memory consumption due to the handling of untrusted inputs. These inputs cause the message broker to consume large amounts of memory, resulting in the application being terminated by the operating system.

Frequently asked questions

What is CVE-2021-33176?: VerneMQ MQTT Broker versions prior to 1.12.0 are vulnerable to a denial of service attack as a result of excessive memory consumption due to the handling of untrusted inputs. These inputs cause the message broker to consume large amounts of memory, resulting in the application being terminated by the operating system.
How severe is CVE-2021-33176?: CVE-2021-33176 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 none, integrity none, and availability high.
Is CVE-2021-33176 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-33176?: CVE-2021-33176 affects Octavolabs Vernemq. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-33176?: 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-2021-33176 published?: CVE-2021-33176 was published on 2021-06-08 and last updated on 2026-06-17.

References

https://www.synopsys.com/blogs/software-security/cyrc-advisory-rabbitmq-emqx-vernemq

Affected products (1)

cpe:2.3:a:octavolabs:vernemq:*:*:*:*:*:*:*:*

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