Mozilla Firefox for iOS up to 159.x Remote Code Execution

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
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.
7.0$5k-$25k0.00+

Summaryinfo

A vulnerability was found in Mozilla Firefox for iOS up to 159.x and classified as critical. This vulnerability affects unknown code. Executing a manipulation can lead to Remote Code Execution. This vulnerability is registered as CVE-2026-121841. It is possible to launch the attack remotely. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Mozilla Firefox for iOS up to 159.x. It has been declared as critical. This vulnerability affects an unknown code. The manipulation with an unknown input leads to a remote code execution vulnerability. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Other issue in Firefox for iOS. This vulnerability was fixed in Firefox for iOS 160.0.

The advisory is available at bugzilla.mozilla.org. This vulnerability was named CVE-2026-121841 since 11/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 11/09/2026).

Upgrading to version 160.0 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: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
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: Remote Code Execution
CWE: Unknown
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 for iOS 160.0

Timelineinfo

11/04/2026 CVE reserved
11/09/2026 +5 days Advisory disclosed
11/09/2026 +0 days VulDB entry created
11/09/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CNA: mozilla
CVE: CVE-2026-121841 (🔒)

GCVE (CVE): GCVE-0-2026-121841
GCVE (VulDB): GCVE-100-433150

Entryinfo

Created: 11/09/2026 15:02
Changes: 11/09/2026 15:02 (55)
Complete: 🔍
Cache ID: 216::103

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Discussion

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