CVE-2024-4776Public exploitNetwork attack vector

Browser interaction lockout via restored disabled state

Published May 14, 2024 · Updated Aug 1, 2024

Denial of service in Mozilla Firefox before 126 allows remote attackers to leave a browser window unresponsive through a crafted webpage. On Windows, fullscreen-entry logic cached all window-style flags, including WS_DISABLED, and fullscreen exit restored that disabled state after a file dialog closed. When a user visits the page, enters full-screen mode, opens a file picker, and dismisses it, the affected Firefox window stops accepting input and can require process termination.

CVSS severity8.2
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Denial of service in Mozilla Firefox before 126 allows remote attackers to leave a browser window unresponsive through a crafted webpage. On Windows, fullscreen-entry logic cached all window-style flags, including WS_DISABLED, and fullscreen exit restored that disabled state after a file dialog closed. When a user visits the page, enters full-screen mode, opens a file picker, and dismisses it, the affected Firefox window stops accepting input and can require process termination.

The record

CVE
CVE-2024-4776
Published
May 14, 2024
Updated
Aug 1, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-79, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 14, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 1, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=- <126
  2. Affected versionversion=unspecified <126

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=- <126; version=unspecified <126

Published CVSS scores

8.2CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:H

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')
T1499Endpoint Denial of Service

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo