CVE-2026-78997Public exploitNetwork attack vector

Cross-origin JavaScript execution via deferred bridge callback

Published Sep 8, 2026 · Updated Sep 9, 2026

Universal XSS in UC Browser for Android 13.7.8.1314 allows remote attackers to execute JavaScript in any origin via a crafted URL. Its internal JavaScript bridge retains a deferred callback across tab navigation and invokes it under the destination origin when a login dialog is dismissed. Exploitation requires user interaction with the crafted flow and grants script access to data and actions permitted by the victim site.

CVSS severity9.3
Critical
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Universal XSS in UC Browser for Android 13.7.8.1314 allows remote attackers to execute JavaScript in any origin via a crafted URL. Its internal JavaScript bridge retains a deferred callback across tab navigation and invokes it under the destination origin when a login dialog is dismissed. Exploitation requires user interaction with the crafted flow and grants script access to data and actions permitted by the victim site.

The record

CVE
CVE-2026-78997
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

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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