CVE-2021-22160 | Authentication with JWT allows use of “none”-algorithm

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).

Published: 2021-05-26 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-22160 is rated High Risk (78.8/100): CVSS Critical severity, with high exploitation likelihood (EPSS 52.93%, 99th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +34.40% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-22160

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 18.53% 52.93% +34.40%
2 2025-11-21 23.27% 18.53% -4.74%
3 2025-11-18 — 23.27% —

Full EPSS history (27 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-22160

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2021-22160

GitHub Security Advisory for CVE-2021-22160

GHSA-3cv4-xxv7-934q · Severity: critical · Ecosystem: maven — Improper Verification of Cryptographic Signature in Apache Pulsar in TensorFlow

Affected software / configurations for CVE-2021-22160

Vendor Product Version Raw CPE
apache pulsar < 2.7.1 cpe:2.3:a:apache:pulsar:*:*:*:*:*:*:*:*

References for CVE-2021-22160

URL Tags
https://lists.apache.org/thread.html/r347650d15a3e9c5f58b83e918b6ad6dedc2a63d3eb63da8e6a7be87e%40%3Cusers.pulsar.apache.org%3E Mailing List Vendor Advisory
https://lists.apache.org/thread.html/r8e545559781231a83bf0644548c660255859e52feb86bbfcd42590da%40%3Cdev.pulsar.apache.org%3E
https://lists.apache.org/thread.html/r9a12b4da2f26ce9b8f7e7117a879efaa973dab7e54717bbc7923fab1%40%3Cdev.pulsar.apache.org%3E Mailing List Vendor Advisory
https://lists.apache.org/thread.html/ra49cb62105154e4795b259c79a6b27d63bfa2ab5787ff8529b089550%40%3Cdev.pulsar.apache.org%3E
https://lists.apache.org/thread.html/ra49cb62105154e4795b259c79a6b27d63bfa2ab5787ff8529b089550%40%3Cusers.pulsar.apache.org%3E
https://lists.apache.org/thread.html/rbe845aa1573a61769b9c5916c62971f4b10de87c2ea5f38a97f0cf84%40%3Cdev.pulsar.apache.org%3E
https://lists.apache.org/thread.html/rca54f4b26ba5e6f2e39732b47ec51640e89f57e3b6a38ac3bab314df%40%3Cdev.pulsar.apache.org%3E
https://lists.apache.org/thread.html/rf2e90942996dceebac8296abf39257cfeb5ae918f82f7af3d37a48c5%40%3Cdev.pulsar.apache.org%3E
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