CVE-2023-4579Network attack vector

Site spoofing via URL-formatted search terms

Published Sep 11, 2023 · Updated Dec 18, 2025

Search spoofing in Mozilla Firefox before 117 allows remote attackers to make a crafted search query appear as the current URL and imitate another site. The default search engine formats a well-formed URL search term as navigated-address text, so the address bar can display an attacker-chosen site while the query remains a search. Exploitation requires a maliciously configured default search engine and user navigation of the crafted query; the reported consequence is integrity-impacting visual spoofing rather than data disclosure or code execution.

CVSS severity3.1
Low
EPSS probability0.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Search spoofing in Mozilla Firefox before 117 allows remote attackers to make a crafted search query appear as the current URL and imitate another site. The default search engine formats a well-formed URL search term as navigated-address text, so the address bar can display an attacker-chosen site while the query remains a search. Exploitation requires a maliciously configured default search engine and user navigation of the crafted query; the reported consequence is integrity-impacting visual spoofing rather than data disclosure or code execution.

The record

CVE
CVE-2023-4579
Published
Sep 11, 2023
Updated
Dec 18, 2025
Vendor
Mozilla
Product
Firefox
Classifications
T1566
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Dec 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 <117

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <117

Published CVSS scores

3.1NVDCVSS:3.1/AV:N/AC:H/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.

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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

T1566Phishing

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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