VDB-370117 · CVE-2026-11799 · GCVE-0-2026-11799

Mozilla Focus/Klar up to 151.3.0 on iOS cross site scripting

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.
4.1	$0-$5k	0.78

Summaryinfo

A vulnerability classified as critical has been found in Mozilla Focus and Klar up to 151.3.0 on iOS. Affected by this vulnerability is an unknown functionality. This manipulation causes cross site scripting. This vulnerability is tracked as CVE-2026-11799. The attack is possible to be carried out remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Mozilla Focus and Klar up to 151.3.0 on iOS. Affected by this vulnerability is some unknown processing. The manipulation with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is 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. As an impact it is known to affect integrity. The summary by CVE is:

UXSS in Focus for iOS / Klar Webkit navigation. This vulnerability was fixed in Focus for iOS 151.3.1 and Klar for iOS 151.3.1.

The advisory is shared at bugzilla.mozilla.org. This vulnerability is known as CVE-2026-11799 since 06/09/2026. 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 $0-$5k at the moment (estimation calculated on 06/10/2026). MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

Upgrading to version 151.3.1 eliminates this vulnerability.

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Productinfo

Type

Web Browser

Vendor

Mozilla

Name

Version

License

open-source

Website

Vendor: https://www.mozilla.org/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.3
VulDB Meta Temp Score: 4.1

VulDB Base Score: 4.3
VulDB Temp Score: 4.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Focus/Klar 151.3.1

Timelineinfo

06/09/2026 CVE reserved
06/10/2026 +1 days Advisory disclosed
06/10/2026 +0 days VulDB entry created
06/10/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CVE: CVE-2026-11799 (🔒)
GCVE (CVE): GCVE-0-2026-11799
GCVE (VulDB): GCVE-100-370117

Entryinfo

Created: 06/10/2026 07:01
Changes: 06/10/2026 07:01 (56)
Complete: 🔍
Cache ID: 216::103