How severe is CVE-2021-22160?

CVE-2021-22160 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-22160 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 53% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-22160?

CVE-2021-22160 affects Apache Pulsar. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-22160?

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-2021-22160 published?

CVE-2021-22160 was published on 2021-05-26 and last updated on 2026-06-17.

CVE-2021-22160

CVE-2021-22160 is a critical-severity vulnerability in Apache Pulsar with a CVSS 3.x base score of 9.8. Its EPSS exploit-prediction score of 53% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-347.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 53% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-347
Affected product: Apache Pulsar
Published: 2021-05-26
Last modified: 2026-06-17

Description

If Apache Pulsar is configured to authenticate clients using tokens based on JSON Web Tokens (JWT), the signature of the token is not validated if the algorithm of the presented token is set to "none". This allows an attacker to connect to Pulsar instances as any user (incl. admins).

Frequently asked questions

What is CVE-2021-22160?: If Apache Pulsar is configured to authenticate clients using tokens based on JSON Web Tokens (JWT), the signature of the token is not validated if the algorithm of the presented token is set to "none". This allows an attacker to connect to Pulsar instances as any user (incl. admins).
How severe is CVE-2021-22160?: CVE-2021-22160 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-22160 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 53% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-22160?: CVE-2021-22160 affects Apache Pulsar. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-22160?: 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-2021-22160 published?: CVE-2021-22160 was published on 2021-05-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:apache:pulsar:*:*:*:*:*:*:*:*

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