XSS in N/a

CVE-2026-78997

UC Browser for Android (package com.UCMobile.intl, version 13.7.8.1314) contains a Universal Cross-Site Scripting vulnerability that allows an attacker to execute arbitrary JavaScript in the context of any origin. An attacker hosts a specially crafted URL on a UC-owned domain (via a reflected XSS) that leverages the browser's internal JavaScript bridge to register a deferred callback, navigate the tab to a victim site, and then execute attacker-controlled code on that site when a login dialog is dismissed.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (33.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 33rd percentile — 33.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-78997: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-78997?
CVE-2026-78997 is a critical-severity vulnerability in N/a, classified under Cross-site Scripting. CVSS score: 9.3/10. Published 2026-09-08.
How severe is CVE-2026-78997?
Critical severity. CVSS v3 base score is 9.3 out of 10.
Is CVE-2026-78997 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.