CVE-2026-40451Network attack vector

Script execution via unsanitized DOM rendering

Published Apr 22, 2026 · Updated Apr 22, 2026

Cross-site scripting in DeepL for Chrome 1.22.0 through 1.23.0 allows remote attackers to execute scripts through crafted input. The extension renders user-controlled search queries or page content into the DOM without complete sanitization, allowing injected HTML and JavaScript to run in the browser context. Exploitation requires active user interaction; resulting script execution can read or modify content available to the affected browser page.

CVSS severity5.1
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in DeepL for Chrome 1.22.0 through 1.23.0 allows remote attackers to execute scripts through crafted input. The extension renders user-controlled search queries or page content into the DOM without complete sanitization, allowing injected HTML and JavaScript to run in the browser context. Exploitation requires active user interaction; resulting script execution can read or modify content available to the affected browser page.

The record

CVE
CVE-2026-40451
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
DeepL
Product
DeepL for Chrome
Classifications
CWE-79, CWE-80, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=from v1.22.0 to v.1.23.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

DeepL · DeepL for Chromeversion=from v1.22.0 to v.1.23.0

Published CVSS scores

5.1JPCERT/CCCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
6.1JPCERT/CCCVSS:3.0/AV:N/AC:L/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 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')
CWE-80Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
T1203Exploitation for Client Execution

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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