Mozilla Firefox up to 153.1/154 Navigation cross site scripting

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.6$0-$5k0.00

Summaryinfo

A vulnerability marked as critical has been reported in Mozilla Firefox up to 153.1/154. This affects an unknown function of the component Navigation. The manipulation leads to Remote Code Execution. This vulnerability is referenced as CVE-2026-84136. Remote exploitation of the attack is possible. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mozilla Firefox up to 153.1/154 and classified as critical. This issue affects an unknown code of the component Navigation. The manipulation with an unknown input leads to a remote code execution vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Other issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

The advisory is shared at bugzilla.mozilla.org. The identification of this vulnerability is CVE-2026-84136 since 09/01/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/23/2026). MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 342301 (Linux Distros Unpatched Vulnerability : CVE-2026-84136), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 153.2 or 155 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (342301) and CERT Bund (WID-SEC-2026-3132). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Debian Linux
  • Red Hat Enterprise Linux
  • IGEL OS
  • SUSE Linux
  • SUSE openSUSE
  • Oracle 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: 7.7
VulDB Meta Temp Score: 7.6

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 6.1
NVD Vector: 🔒

ADP CISA Base Score: 9.8
ADP CISA Vector: 🔒

CVSSv2info

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

Exploitinginfo

Class: Cross site scripting
CWE: CWE-79 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 342301
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-84136

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 153.2/155

Timelineinfo

09/01/2026 Advisory disclosed
09/01/2026 +0 days CVE reserved
09/01/2026 +0 days VulDB entry created
09/23/2026 +22 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-84136 (🔒)
GCVE (CVE): GCVE-0-2026-84136
GCVE (VulDB): GCVE-100-397625
CERT Bund: WID-SEC-2026-3132 - Mozilla Firefox und Thunderbird: Mehrere Schwachstellen

Entryinfo

Created: 09/01/2026 15:14
Updated: 09/23/2026 06:34
Changes: 09/01/2026 15:14 (56), 09/03/2026 02:18 (2), 09/07/2026 05:28 (23), 09/08/2026 08:03 (7), 09/23/2026 06:34 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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