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Pulsar CVE-2023-37544

HIGH
Improper Authentication (CWE-287)
2023-12-20 security@apache.org
7.5
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication mechanism validation
MITRE ATT&CK

2 techniques across 2 tactics: Defense Evasion, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could bypass authentication mechanisms to gain unauthorized access by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 1.4% exploitation probability (EPSS)

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AnalysisAI

Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.8.0 through 2.8.*, from 2.9.0 through 2.9.*, from. Rated high severity (CVSS 7.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement multi-factor authentication, enforce strong password policies, use proven authentication frameworks.

Affected Packages

maven org.apache.pulsar:pulsar-websocket fix: 2.10.5, 2.11.2, 3.0.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in maven

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Improper Authentication (CWE-287), which allows attackers to bypass authentication mechanisms to gain unauthorized access. Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.8.0 through 2.8.*, from 2.9.0 through 2.9.*, from 2.10.0 through 2.10.4, from 2.11.0 through 2.11.1, 3.0.0. The known risks include a denial of service due to the WebSocket Proxy accepting any connections, and excessive data transfer due to misuse of the WebSocket ping/pong feature. 2.10 Pulsar WebSocket Proxy users should upgrade to at least 2.10.5. 2.11 Pulsar WebSocket Proxy users should upgrade to at least 2.11.2. 3.0 Pulsar WebSocket Proxy users should upgrade to at least 3.0.1. 3.1 Pulsar WebSocket Proxy users are unaffected. Any users running the Pulsar WebSocket Proxy for 2.8, 2.9, and earlier should upgrade to one of the above patched versions. Affected products include: Apache Pulsar. Version information: through 2.8..

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Severity by source

NVD PRIMARY 7.5 HIGH
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

DescriptionNVD

Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.

This issue affects Apache Pulsar WebSocket Proxy: from 2.8.0 through 2.8.*, from 2.9.0 through 2.9.*, from 2.10.0 through 2.10.4, from 2.11.0 through 2.11.1, 3.0.0.

The known risks include a denial of service due to the WebSocket Proxy accepting any connections, and excessive data transfer due to misuse of the WebSocket ping/pong feature.

2.10 Pulsar WebSocket Proxy users should upgrade to at least 2.10.5. 2.11 Pulsar WebSocket Proxy users should upgrade to at least 2.11.2. 3.0 Pulsar WebSocket Proxy users should upgrade to at least 3.0.1. 3.1 Pulsar WebSocket Proxy users are unaffected. Any users running the Pulsar WebSocket Proxy for 2.8, 2.9, and earlier should upgrade to one of the above patched versions.

Threat Intelligence Overview

EPSS Score
1.4%
Top 32% exploitable
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 1.4%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact· derived
Medium

Priority Score

39
Low Medium High Critical
KEV: 0
EPSS: +1
CVSS: +38
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:apache:pulsar:*:*:*:*:*:*:*:*
cpe:2.3:a:apache:pulsar:*:*:*:*:*:*:*:*
cpe:2.3:a:apache:pulsar:3.0.0:*:*:*:*:*:*:*

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