CVE-2026-13042Network attack vector

Unauthenticated stored XSS via render-time attribute synthesis

Published Jul 16, 2026 · Updated Jul 16, 2026

Stored cross-site scripting in yo35 RPB Chessboard 8.1.2 and earlier allows remote attackers to execute scripts via crafted comment content. The comment_text filter assembles attribute-bearing HTML from kses-allowed comment fragments without contextual output escaping, synthesizing an attribute break only during rendering. No account is required to submit the crafted content; script execution occurs when a user views the affected page and is limited to that visitor's browser context.

CVSS severity7.2
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored cross-site scripting in yo35 RPB Chessboard 8.1.2 and earlier allows remote attackers to execute scripts via crafted comment content. The comment_text filter assembles attribute-bearing HTML from kses-allowed comment fragments without contextual output escaping, synthesizing an attribute break only during rendering. No account is required to submit the crafted content; script execution occurs when a user views the affected page and is limited to that visitor's browser context.

The record

CVE
CVE-2026-13042
Published
Jul 16, 2026
Updated
Jul 16, 2026
Vendor
yo35
Product
RPB Chessboard
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 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 <=8.1.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

yo35 · RPB Chessboardversion=0 <=8.1.2

Published CVSS scores

7.2WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 exploitUnconfirmed

Weakness, pattern, technique

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

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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