CVE-2026-40451 Cross-site scripting in Chrome browser extension
An attacker can execute arbitrary scripts and inject malicious HTML into web pages viewed by users of the DeepL Chrome extension.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-40451?
CVE-2026-40451 is a medium-severity cross-site scripting vulnerability in DeepL Chrome browser extension, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
DeepL Chrome browser extension versions from v1.22.0 to v.1.23.0 contain a cross-site scripting vulnerability, which allows an attacker to execute arbitrary script in a user's browser, and inject malicious HTML into web pages viewed by the user.
Weakness: CWE-79
Which versions are affected by CVE-2026-40451?
How do I fix CVE-2026-40451?
No fix has been published for CVE-2026-40451 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-40451 being exploited?
There is no known exploitation of CVE-2026-40451 in the wild and no public exploit code.