CVE-2026-9959Network attack vectorHinoki check available

Cross-origin data leak via WebRTC race

Published May 28, 2026 · Updated May 28, 2026

A WebRTC race in Google Chrome on Windows before 148.0.7778.216 allows remote attackers to leak cross-origin data via a crafted HTML page. The published record does not identify the racing WebRTC operation or the synchronization failure that exposes data across origins. Exploitation requires a Windows user to load the crafted page; the documented consequence is data disclosure, not code execution or data modification.

CVSS severity3.1
Low
EPSS probability0.14%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

A WebRTC race in Google Chrome on Windows before 148.0.7778.216 allows remote attackers to leak cross-origin data via a crafted HTML page. The published record does not identify the racing WebRTC operation or the synchronization failure that exposes data across origins. Exploitation requires a Windows user to load the crafted page; the documented consequence is data disclosure, not code execution or data modification.

The record

CVE
CVE-2026-9959
Published
May 28, 2026
Updated
May 28, 2026
Vendor
WebM Project
Product
Chrome
Classifications
CWE-362
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 28, 2026CVE publishedPublication date reported by the CVE source.
  2. May 28, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected version<148.0.7778.216

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WebM Project · Chrome<148.0.7778.216

Published CVSS scores

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

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

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Your stack

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