Mozilla Firefox up to 82.x on Android Fullscreen ui layer

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.2$0-$5k0.00

Summaryinfo

A vulnerability was found in Mozilla Firefox up to 82.x on Android and classified as critical. Affected by this vulnerability is an unknown functionality of the component Fullscreen Handler. The manipulation results in ui layer. This vulnerability is reported as CVE-2020-26954. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Mozilla Firefox up to 82.x on Android (Web Browser). Affected is an unknown code of the component Fullscreen Handler. The manipulation with an unknown input leads to a ui layer vulnerability. CWE is classifying the issue as CWE-1021. The web application does not restrict or incorrectly restricts frame objects or UI layers that belong to another application or domain, which can lead to user confusion about which interface the user is interacting with. This is going to have an impact on confidentiality, integrity, and availability.

The weakness was disclosed 12/09/2020 as mfsa2020-50. The advisory is shared for download at mozilla.org. This vulnerability is traded as CVE-2020-26954. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 02/09/2026).

The vulnerability scanner Nessus provides a plugin with the ID 247761 (Linux Distros Unpatched Vulnerability : CVE-2021-23976), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 83.0 eliminates this vulnerability. The upgrade is hosted for download at mozilla.org.

The vulnerability is also documented in the databases at Tenable (247761) and CERT Bund (WID-SEC-2026-0337). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Open Source CentOS
  • Debian Linux
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • Gentoo Linux
  • Open Source Arch Linux
  • Mozilla Firefox
  • Mozilla Firefox ESR
  • Mozilla Thunderbird

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.2

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 4.3
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Ui layer
CWE: CWE-1021
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
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Nessus ID: 247761
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2021-23976

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Firefox 83.0

Timelineinfo

10/12/2020 🔍
12/09/2020 +58 days 🔍
12/09/2020 +0 days 🔍
02/09/2026 +1888 days 🔍

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: mfsa2020-50
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2020-26954 (🔍)
GCVE (CVE): GCVE-0-2020-26954
GCVE (VulDB): GCVE-100-165792
CERT Bund: WID-SEC-2026-0337 - Mozilla Firefox und Thunderbird: Mehrere Schwachstellen

scip Labs: https://www.scip.ch/en/?labs.20130704

Entryinfo

Created: 12/09/2020 10:40
Updated: 02/09/2026 10:28
Changes: 12/09/2020 10:40 (44), 12/14/2020 08:08 (6), 12/14/2020 08:11 (18), 08/12/2025 02:42 (17), 02/09/2026 10:28 (7)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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