CVE-2023-49805Public exploitNetwork attack vector

Cross-origin application access via unchecked WebSocket origins

Published Dec 11, 2023 · Updated Aug 2, 2024

Origin validation failure in Louis Lam Uptime Kuma before 1.23.9 allows remote attackers to open cross-origin WebSocket connections. The Socket.IO connection handler accepts an Origin header whose hostname differs from the Host header, letting third-party JavaScript communicate through a client browser. Protected functions still require credentials, but No-auth deployments relying on a firewall or reverse proxy expose full application access.

CVSS severity6.0
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation failure in Louis Lam Uptime Kuma before 1.23.9 allows remote attackers to open cross-origin WebSocket connections. The Socket.IO connection handler accepts an Origin header whose hostname differs from the Host header, letting third-party JavaScript communicate through a client browser. Protected functions still require credentials, but No-auth deployments relying on a firewall or reverse proxy expose full application access.

The record

CVE
CVE-2023-49805
Published
Dec 11, 2023
Updated
Aug 2, 2024
Vendor
Louis Lam
Product
Uptime Kuma
Classifications
CWE-1385, T1190
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.23.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Louis Lam · Uptime Kumaversion=< 1.23.9

Published CVSS scores

8.8GitLab Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.0GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1385Missing Origin Validation in WebSockets
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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