CVE-2024-4773Public exploitNetwork attack vector

Website spoofing via retained network-error content

Published May 14, 2024 · Updated Aug 1, 2024

URL-bar spoofing in Mozilla Firefox before 126 allows remote attackers to hide a spoofed site's source after a page-load network error. The navigation path handled DONT_RETARGET before checking NS_ERROR_FILE_NOT_FOUND, leaving prior content visible while clearing the URL bar. A crafted application/octet-stream endpoint must produce the network error; the retained content is inert and only obscures its actual source.

CVSS severity7.5
High
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

URL-bar spoofing in Mozilla Firefox before 126 allows remote attackers to hide a spoofed site's source after a page-load network error. The navigation path handled DONT_RETARGET before checking NS_ERROR_FILE_NOT_FOUND, leaving prior content visible while clearing the URL bar. A crafted application/octet-stream endpoint must produce the network error; the retained content is inert and only obscures its actual source.

The record

CVE
CVE-2024-4773
Published
May 14, 2024
Updated
Aug 1, 2024
Vendor
Mozilla
Product
Firefox
Classifications
CWE-601, T1598.003
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

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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=0 <126
  2. Affected versionversion=unspecified <126

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=0 <126; version=unspecified <126

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-601URL Redirection to Untrusted Site ('Open Redirect')
T1598.003Phishing for Information: Spearphishing Link

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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