Mozilla Firefox up to 153.4/157 File privileges assignment

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
6.0$5k-$25k0.73-

Summaryinfo

A vulnerability was found in Mozilla Firefox up to 153.4/157. It has been rated as critical. This impacts an unknown function of the component File Handler. This manipulation causes privileges assignment. This vulnerability appears as CVE-2026-109763. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Mozilla Firefox up to 153.4/157 and classified as critical. Affected by this vulnerability is an unknown function of the component File Handler. The manipulation with an unknown input leads to a privileges assignment vulnerability. The CWE definition for the vulnerability is CWE-266. A product incorrectly assigns a privilege to a particular actor, creating an unintended sphere of control for that actor. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Mitigation bypass in the File Handling component. This vulnerability was fixed in Firefox 158 and Firefox ESR 153.5.

The advisory is shared at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-109763 since 10/13/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/13/2026). MITRE ATT&CK project uses the attack technique T1068 for this issue.

Upgrading to version 153.5 or 158 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

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

CVSSv2info

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

Exploitinginfo

Class: Privileges assignment
CWE: CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 153.5/158

Timelineinfo

10/13/2026 Advisory disclosed
10/13/2026 +0 days CVE reserved
10/13/2026 +0 days VulDB entry created
10/13/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-109763 (🔒)
GCVE (CVE): GCVE-0-2026-109763
GCVE (VulDB): GCVE-100-417613

Entryinfo

Created: 10/13/2026 15:39
Changes: 10/13/2026 15:39 (57)
Complete: 🔍
Cache ID: 216::103

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