CVE-2024-9398Network attack vector

Installed-application enumeration via protocol-handler popup results

Published Oct 1, 2024 · Updated Mar 18, 2025

Information disclosure in Firefox before 131, Firefox ESR before 128.3, and Thunderbird before 131 allows remote attackers to enumerate installed applications. Calls to window.open with selected external-protocol URLs return observably different popup results when a corresponding protocol handler is installed. A crafted page can therefore infer application presence without authentication, but no file contents, application data, or write capability are disclosed.

CVSS severity5.3
Medium
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in Firefox before 131, Firefox ESR before 128.3, and Thunderbird before 131 allows remote attackers to enumerate installed applications. Calls to window.open with selected external-protocol URLs return observably different popup results when a corresponding protocol handler is installed. A crafted page can therefore infer application presence without authentication, but no file contents, application data, or write capability are disclosed.

The record

CVE
CVE-2024-9398
Published
Oct 1, 2024
Updated
Mar 18, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-203, T1518
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 1, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 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 <131

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <131
Mozilla · Thunderbirdversion=unspecified <128.3; version=unspecified <131
Mozilla · Firefox ESRversion=unspecified <128.3

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-203Observable Discrepancy
T1518Software Discovery

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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