CVE-2026-40028Network attack vector

Stored XSS via unescaped JSON Computer field

Published Apr 8, 2026 · Updated Apr 8, 2026

Stored XSS in Yamato Security Hayabusa 3.7.0 and earlier allows remote authenticated users to execute JavaScript via crafted JSON logs. The HTML report generator copies the Computer field from JSON-exported logs into browser-rendered output without neutralizing script content. Execution requires a forensic examiner to scan the crafted JSON input and open the generated report, exposing data and actions available to that browser session.

CVSS severity5.1
Medium
EPSS probability0.20%
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 Yamato Security Hayabusa 3.7.0 and earlier allows remote authenticated users to execute JavaScript via crafted JSON logs. The HTML report generator copies the Computer field from JSON-exported logs into browser-rendered output without neutralizing script content. Execution requires a forensic examiner to scan the crafted JSON input and open the generated report, exposing data and actions available to that browser session.

The record

CVE
CVE-2026-40028
Published
Apr 8, 2026
Updated
Apr 8, 2026
Vendor
Yamato Security
Product
Hayabusa
Classifications
CWE-79, CAPEC-592, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2026Record 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=0 <=3.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Yamato Security · Hayabusaversion=0 <=3.7.0

Published CVSS scores

5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
5.4VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-592Stored XSS
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

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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