CVE-2026-15917Network attack vectorHinoki check available

Script execution via unsanitized HTMX attributes

Published Aug 25, 2026 · Updated Aug 26, 2026

Cross-site scripting in Drupal core allows attackers to execute script in users' browsers through crafted HTML containing HTMX attributes. The core XSS filter fails to remove or neutralize certain HTMX attributes before attacker-supplied HTML is rendered. Exploitation requires the ability to insert HTML with those attributes and user rendering of the affected content, bounding the consequence to script execution in the site's browser origin.

CVSS severity4.7
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Cross-site scripting in Drupal core allows attackers to execute script in users' browsers through crafted HTML containing HTMX attributes. The core XSS filter fails to remove or neutralize certain HTMX attributes before attacker-supplied HTML is rendered. Exploitation requires the ability to insert HTML with those attributes and user rendering of the affected content, bounding the consequence to script execution in the site's browser origin.

The record

CVE
CVE-2026-15917
Published
Aug 25, 2026
Updated
Aug 26, 2026
Vendor
OAuth.js
Product
Drupal core
Classifications
CWE-79, CAPEC-63, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 26, 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=0.0.0 <11.2.*
  2. Affected versionversion=11.3.0 <11.3.14
  3. Affected versionversion=11.4.0 <11.4.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OAuth.js · Drupal coreversion=0.0.0 <11.2.*; version=11.3.0 <11.3.14; version=11.4.0 <11.4.4

Published CVSS scores

4.7CISA-ADPCVSS:3.1/AV:N/AC:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
CAPEC-63Cross-Site Scripting (XSS)
T1059.007Command and Scripting Interpreter: JavaScript/JScript

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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