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CVE Record

CVE-2026-13042: RPB Chessboard <= 8.1.2 - Unauthenticated Stored Cross-Site Scripting via Comment Content

The RPB Chessboard plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 8.1.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. WordPress's save-time kses sanitization does not mitigate this issue because the crafted payload uses only kses-allowed tags and attributes (such as an &lt;a&gt; element with title and href), and the dangerous attribute-breaking HTML is synthesized entirely at render time by the plugin's own comment_text filter.

HighCVSS 7.2Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2026-13042 is a stored cross-site scripting flaw in the RPB Chessboard WordPress plugin. An unauthenticated attacker can place script content through comments, and that script can run later for visitors who view the affected page. This can expose browser-session data or enable content manipulation in the affected site context.

Executive priority

Prioritize remediation for public WordPress sites using this plugin. The issue is high severity because outsiders can plant persistent browser-executed content, but active exploitation is not confirmed in the supplied sources.

Technical view

RPB Chessboard versions up to and including 8.1.2 insufficiently sanitize and escape comment content. The issue survives WordPress kses save-time filtering because allowed tags and attributes are transformed by the plugin's comment_text render path into unsafe HTML. The CVE is CWE-79 with CVSS 3.1 score 7.2.

Likely exposure

Exposure is most likely on WordPress sites running RPB Chessboard 8.1.2 or earlier, especially where unauthenticated users can submit comments that the plugin later renders.

Exploitation context

The source bundle states unauthenticated stored XSS is possible. It does not provide evidence of active exploitation, and KEV is false. Treat exploit activity as unconfirmed.

Researcher notes

Key evidence points to the plugin's comment_text filter and render-time HTML construction in abstractcontroller.php. The source bundle names kses bypass-by-rendering behavior, but does not include a full vendor advisory or explicit fixed-version statement.

Mitigation direction

  • Update RPB Chessboard beyond 8.1.2 if a fixed vendor release is available.
  • Check Wordfence and plugin vendor guidance for the confirmed fixed version.
  • Temporarily disable unauthenticated comments on affected content until remediated.
  • Review and remove suspicious comments on pages using the plugin.
  • Consider disabling the plugin if no fixed release is available.

Validation and detection

  • Inventory WordPress sites for the RPB Chessboard plugin and installed version.
  • Identify any installations at version 8.1.2 or earlier.
  • Review whether public comments are enabled on affected pages.
  • Inspect recent comments on plugin-rendered pages for suspicious markup.
  • Confirm remediation by verifying the plugin version after update.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-13042 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
High
CVSS
7.2 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
4Timeline events
1ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.2CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N3.92.7Wordfence

Vulnerability scoring details

Base CVSS 3.1 score

7.2High
CVSS 3.1 vector shape for CVE-2026-13042Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. Source timelineWordfence

    Disclosed

  3. CVE publishedCVE Program

    The CVE record was published.

  4. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
yo35RPB Chessboard0unaffected
Weakness

CWE details

CWE-79

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.