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CVE-2023-37544· NVD / CVE Program· CNA apache

Apache Pulsar WebSocket Proxy: Improper Authentication for WebSocket Proxy Endpoint Allows DoS

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.3% (FIRST EPSS); higher than 71% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: org.apache.pulsar:pulsar-websocket (Maven) 2.11.2, 3.0.1, 2.10.5.

Low priority for now. Upgrade to org.apache.pulsar:pulsar-websocket (Maven) 2.11.2, 3.0.1, 2.10.5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

HighCVSS 7.5 · v3.1—No exploit Fix available
Published
Dec 20, 2023
Updated
Jun 17, 2026
EPSS
1.3% · 71th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.3%

CNA vs NVD score

NVD
7.5
CNA · apache
7.5
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-37544

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
apachepulsar

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache pulsarbefore 2.10.5
  • apache pulsar2.11.0 and later · before 2.11.2
  • apache pulsar3.0.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Pulsar WebSocket Proxy

    • 3.0.0affected
    • 2.8.0 and later · up to and including 2.8.*affected · semver
    • 2.9.0 and later · up to and including 2.9.*affected · semver
    • 2.10.0 and later · up to and including 2.10.4affected · semver
    • 2.11.0 and later · up to and including 2.11.1affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.apache.pulsar:pulsar-websocketfrom 2.11.0 · before 2.11.22.11.2
Mavenorg.apache.pulsar:pulsar-websocketfrom 3.0.0 · before 3.0.13.0.1
Mavenorg.apache.pulsar:pulsar-websocketbefore 2.10.52.10.5

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-27317Apache Pulsar: Pulsar Functions Worker's Archive Extraction Vulnerability Allows Unauthorized File Modification
    56Plan
  • CVE-2021-22160Authentication with JWT allows use of “none”-algorithm
    55Plan
  • CVE-2024-27135Apache Pulsar: Improper Input Validation in Pulsar Function Worker allows Remote Code Execution
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2023-31007Jul 12, 2023 · Apache Pulsar: Broker does not always disconnect client when authentication data expires
    26Monitor
  • ← EarlierCVE-2023-37579Jul 12, 2023 · Apache Pulsar Function Worker: Incorrect Authorization for Function Worker Can Leak Sink/Source Credentials
    26Monitor
  • Later →CVE-2023-51437Feb 7, 2024 · Apache Pulsar: Timing attack in SASL token signature verification
    29Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Maven:org.apache.pulsar:pulsar-websocket2.10.5Package registry (OSV)
Maven:org.apache.pulsar:pulsar-websocket2.11.2Package registry (OSV)
Maven:org.apache.pulsar:pulsar-websocket3.0.1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2023-31007161 days apartApache Pulsar: Broker does not always disconnect client when authentication data expires
    26Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2024-2731783 days apartApache Pulsar: Pulsar Functions Worker's Archive Extraction Vulnerability Allows Unauthorized File Modification
    56Plan
  • CVE-2024-2713583 days apartApache Pulsar: Improper Input Validation in Pulsar Function Worker allows Remote Code Execution
    41Plan

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

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

nvd-primary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);

Fixed

ts
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records