CVE-2023-37207Public exploitNetwork attack vector

Spoofing via persistent fullscreen during external handler launch

Published Jul 5, 2023 · Updated Feb 13, 2025

Fullscreen spoofing in Mozilla Firefox before 115, Firefox ESR before 102.13, and Thunderbird before 102.13 allows remote attackers to mislead users. When a malicious page requests fullscreen while opening an externally handled URL such as mailto, the browser leaves fullscreen active as the maximized external application hides its notification. The user must activate the page control; the hidden notification lets a spoofed page remain behind the external window and be mistaken for trusted content.

CVSS severity6.5
Medium
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Fullscreen spoofing in Mozilla Firefox before 115, Firefox ESR before 102.13, and Thunderbird before 102.13 allows remote attackers to mislead users. When a malicious page requests fullscreen while opening an externally handled URL such as mailto, the browser leaves fullscreen active as the maximized external application hides its notification. The user must activate the page control; the hidden notification lets a spoofed page remain behind the external window and be mistaken for trusted content.

The record

CVE
CVE-2023-37207
Published
Jul 5, 2023
Updated
Feb 13, 2025
Vendor
Mozilla
Product
Firefox
Classifications
CWE-470
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 5, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <115

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mozilla · Firefoxversion=unspecified <115
Mozilla · Thunderbirdversion=unspecified <102.13
Mozilla · Firefox ESRversion=unspecified <102.13

Published CVSS scores

6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/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 exploitPublished

Weakness, pattern, technique

CWE-470Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo