CVE-2026-78997: XSS (CVSS 9.3)

Description

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.

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CVSS v3.1 Score

9.3

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0028

Probability of exploitation

0.20%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

References

Other References

https://gist.github.com/OmriInbar-Novee/9fd65fe08c1b1cff6a19350e44425de2 https://gist.github.com/OmriInbar-Novee/ef7a92db148b2eb1ab0aa7b99a565c4c https://gist.github.com/OmriInbar-Novee/9fd65fe08c1b1cff6a19350e44425de2

Frequently Asked Questions

What is 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. It has a CVSS v3.1 base score of 9.3 (CRITICAL).

How severe is CVE-2026-78997? +

CVE-2026-78997 has a CVSS v3.1 score of 9.3 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0028, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-78997? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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