CVE-2022-26383Public exploitNetwork attack vector

Browser-window spoofing via fullscreen popup resizing

Published Dec 22, 2022 · Updated Apr 16, 2025

UI spoofing in Mozilla Firefox before 98, Firefox ESR before 91.7, and Thunderbird before 91.7 allows remote attackers to hide fullscreen alerts. During a popup's fullscreen transition, resizeBy() or resizeTo() changes its size without forcing fullscreen exit, moving the notification outside the viewport. A malicious webpage requires user interaction to enter fullscreen; the concealed indicator then enables browser-window impersonation, while Thunderbird is exposed only in browser-like contexts.

CVSS severity4.3
Medium
EPSS probability0.66%
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

UI spoofing in Mozilla Firefox before 98, Firefox ESR before 91.7, and Thunderbird before 91.7 allows remote attackers to hide fullscreen alerts. During a popup's fullscreen transition, resizeBy() or resizeTo() changes its size without forcing fullscreen exit, moving the notification outside the viewport. A malicious webpage requires user interaction to enter fullscreen; the concealed indicator then enables browser-window impersonation, while Thunderbird is exposed only in browser-like contexts.

The record

CVE
CVE-2022-26383
Published
Dec 22, 2022
Updated
Apr 16, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-451, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 22, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 16, 2025Record 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=unspecified <98

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <98
Mozilla · Thunderbirdversion=unspecified <91.7
Mozilla · Firefox ESRversion=unspecified <91.7

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/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-451User Interface (UI) Misrepresentation of Critical Information
T1036Masquerading

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