CVE-2023-4579VulnerabilityPublished 11 Sep 2023Updated 18 Dec 2025

CVE-2023-4579: Mozilla Firefox · Vulnerability

Affects Mozilla FirefoxSource CVE Database V5

Not known to be exploited : upgrade to 117 when convenient.

Data as of 25 Oct 2026, 21:28 UTC

Severity

Medium

Rated Medium by the CNA (mozilla) · No CVSS score from NVD or the CNA

EPSS: 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 117

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Sep 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Mozilla Firefox to 117.

Affected software

Product	Affected	Fixed in
Mozilla Firefox	Affected <117	Fixed in 117

AI-suggested

Mozilla fixed this vulnerability in Firefox version 117. Users and administrators should update to Firefox 117 or later to remediate this issue. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2023-4579 is a vulnerability in Mozilla Firefox versions prior to 117 where search queries in the default search engine could be displayed as the currently navigated URL if the query itself was a well-formed URL. This behavior could allow a maliciously set default search engine to spoof another site. The issue was fixed in Firefox 117.

Impact

The vulnerability could allow an attacker who controls the default search engine to spoof the displayed URL, misleading users about the site they are visiting. This could facilitate phishing or other social engineering attacks by making a malicious site appear as a legitimate one in the browser's URL display. There is no indication of remote code execution or memory corruption from this specific issue.

Summary

This vulnerability involves the formatting of persisted search terms in Firefox's default search engine. If a search query was a well-formed URL, it could appear as the current URL in the browser, potentially enabling site spoofing if the default search engine was maliciously configured. The flaw affects Firefox versions before 117 and was addressed by Mozilla in Firefox 117.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Oct 2026, 21:28 UTC

Technical details

References

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