CVE-2026-77115 Brave Popup Builder < 0.8.6 - Unauthenticated Reflected XSS via UTM Parameters
Unauthenticated attackers can execute arbitrary scripts in victim browsers via reflected XSS in Brave Popup Builder plugin.
- 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-2026-77115?
CVE-2026-77115 is a high-severity cross-site scripting vulnerability in Unknown Brave, published on 23 Aug 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
Brave Popup Builder (brave-popup-builder) up to version 0.8.5 reflects UTM query parameters into popup form HTML without escaping them.
Weakness: CWE-79
Which versions are affected by CVE-2026-77115?
How do I fix CVE-2026-77115?
No fix has been published for CVE-2026-77115 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-2026-77115 being exploited?
There is no known exploitation of CVE-2026-77115 in the wild and no public exploit code.
Sources
Also known as GHSA-x2v4-r59f-8jxr.