CVE-2026-81571Network attack vector

Unauthenticated shortcode execution via unsanitized UTM parameter

Published Sep 2, 2026 · Updated Sep 2, 2026

Shortcode injection in Brave Popup Builder before 0.8.8 allows remote attackers to execute registered WordPress shortcodes via a UTM parameter. A URL parameter used to pre-fill a form field reaches WordPress's shortcode engine without filtering shortcode syntax. No authentication is required, and impact depends on the capabilities exposed by shortcodes registered on the affected site.

CVSS severity4.8
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Shortcode injection in Brave Popup Builder before 0.8.8 allows remote attackers to execute registered WordPress shortcodes via a UTM parameter. A URL parameter used to pre-fill a form field reaches WordPress's shortcode engine without filtering shortcode syntax. No authentication is required, and impact depends on the capabilities exposed by shortcodes registered on the affected site.

The record

CVE
CVE-2026-81571
Published
Sep 2, 2026
Updated
Sep 2, 2026
Vendor
Brave
Product
Brave Popup Builder
Classifications
CWE-74, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 2, 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 <0.8.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Brave · Brave Popup Builderversion=0 <0.8.8

Published CVSS scores

4.8WPScanCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/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.

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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-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1190Exploit Public-Facing Application

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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