CVE-2023-26777Public exploitNetwork attack vector

Stored XSS via unescaped status-page preload data

Published Apr 4, 2023 · Updated Feb 13, 2025

Stored XSS in Uptime Kuma 1.19.6 and earlier allows remote attackers to execute JavaScript through crafted status-page content. Status-page generation embeds saved title, description, footer, and incident values in window.preloadData without escaping closing script tags. A visitor must load the affected status page; the script then runs in that browser's Uptime Kuma origin and can read or alter page-visible data.

CVSS severity6.1
Medium
EPSS probability0.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Uptime Kuma 1.19.6 and earlier allows remote attackers to execute JavaScript through crafted status-page content. Status-page generation embeds saved title, description, footer, and incident values in window.preloadData without escaping closing script tags. A visitor must load the affected status page; the script then runs in that browser's Uptime Kuma origin and can read or alter page-visible data.

The record

CVE
CVE-2023-26777
Published
Apr 4, 2023
Updated
Feb 13, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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