CVE-2022-34479Public exploitNetwork attack vector

Address-bar spoofing via premature popup resize

Published Dec 22, 2022 · Updated Apr 15, 2025

UI spoofing in Mozilla Firefox before 102, Firefox ESR before 91.11, and Thunderbird before 102 or 91.11 allows remote attackers to spoof URLs. The GTK widget path applies an app-initiated popup resize before the new window geometry settles, allowing oversized page content to displace the address bar. A user must open a malicious site that creates the popup; Mozilla reproduced the behavior only on Linux, and the result is origin spoofing rather than direct code execution.

CVSS severity6.5
Medium
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

UI spoofing in Mozilla Firefox before 102, Firefox ESR before 91.11, and Thunderbird before 102 or 91.11 allows remote attackers to spoof URLs. The GTK widget path applies an app-initiated popup resize before the new window geometry settles, allowing oversized page content to displace the address bar. A user must open a malicious site that creates the popup; Mozilla reproduced the behavior only on Linux, and the result is origin spoofing rather than direct code execution.

The record

CVE
CVE-2022-34479
Published
Dec 22, 2022
Updated
Apr 15, 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 15, 2025Record 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 versionversion=unspecified <102

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <102
Mozilla · Thunderbirdversion=unspecified <102; version=unspecified <91.11
Mozilla · Firefox ESRversion=unspecified <91.11

Published CVSS scores

6.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/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.

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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

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Your stack

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