CVE-2024-8386Network attack vector

Cross-site UI spoofing via popup-overlaid Select elements

Published Sep 3, 2024 · Updated Nov 21, 2024

UI spoofing in Mozilla Firefox before 130, Firefox ESR before 128.2, and Thunderbird before 128.2 allows remote attackers to impersonate sites. A site with permission to open popup windows can place Select elements above content from another site, creating a deceptive cross-site interface. The victim must grant popup permission and interact with attacker-controlled content; the documented consequence is visual spoofing, not code execution.

CVSS severity6.1
Medium
EPSS probability0.39%
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 130, Firefox ESR before 128.2, and Thunderbird before 128.2 allows remote attackers to impersonate sites. A site with permission to open popup windows can place Select elements above content from another site, creating a deceptive cross-site interface. The victim must grant popup permission and interact with attacker-controlled content; the documented consequence is visual spoofing, not code execution.

The record

CVE
CVE-2024-8386
Published
Sep 3, 2024
Updated
Nov 21, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-290, CWE-601
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 21, 2024Record 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 <130

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <130
Mozilla · Thunderbirdversion=unspecified <128.2
Mozilla · Firefox ESRversion=unspecified <128.2

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-290Authentication Bypass by Spoofing
CWE-601URL Redirection to Untrusted Site ('Open Redirect')

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

Your stack

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Your stack

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