Mozilla Firefox up to 115.41/140.16/153.3/156 Panning/Zooming isolation

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.
6.0$5k-$25k0.00

Summaryinfo

A vulnerability has been found in Mozilla Firefox up to 115.41/140.16/153.3/156 and classified as critical. This issue affects some unknown processing of the component Panning/Zooming. Performing a manipulation results in isolation. This vulnerability was named CVE-2026-100821. The attack may be initiated remotely. There is no available exploit. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as critical, was found in Mozilla Firefox up to 115.41/140.16/153.3/156. This affects an unknown part of the component Panning/Zooming. The manipulation with an unknown input leads to a isolation vulnerability. CWE is classifying the issue as CWE-653. The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Site isolation issue in the Panning and Zooming component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17.

The advisory is shared at bugzilla.mozilla.org. This vulnerability is uniquely identified as CVE-2026-100821 since 09/26/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. 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 10/25/2026).

The vulnerability scanner Nessus provides a plugin with the ID 371697 (Rocky Linux 9 [CIQ] Security Update: thunderbird / thunderbird-debuginfo / thunderbird-debugsource Multiple Vulnerabilities (crlsa-2026_80694)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 115.42, 140.17, 153.4 or 157 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (371697) and CERT Bund (WID-SEC-2026-3654). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Debian Linux
  • Mozilla Firefox ESR
  • Mozilla Firefox
  • 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: 6.3
VulDB Meta Temp Score: 6.0

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

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

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

Exploitinginfo

Class: Isolation
CWE: CWE-653
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 371697
Nessus Name: Rocky Linux 9 [CIQ] Security Update: thunderbird / thunderbird-debuginfo / thunderbird-debugsource Multiple Vulnerabilities (crlsa-2026_80694)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Firefox 115.42/140.17/153.4/157

Timelineinfo

09/26/2026 CVE reserved
09/29/2026 +3 days Advisory disclosed
09/29/2026 +0 days VulDB entry created
10/25/2026 +25 days VulDB entry last update

Sourcesinfo

Vendor: mozilla.org
Product: mozilla.org

Advisory: bugzilla.mozilla.org
Status: Confirmed

CNA: mozilla
CVE: CVE-2026-100821 (🔒)

GCVE (CVE): GCVE-0-2026-100821
GCVE (VulDB): GCVE-100-411393
CERT Bund: WID-SEC-2026-3654 - Mozilla Firefox, Firefox ESR und Thunderbird: Mehrere Schwachstellen

Entryinfo

Created: 09/29/2026 15:44
Updated: 10/25/2026 00:00
Changes: 09/29/2026 15:44 (57), 10/04/2026 13:16 (7), 10/25/2026 00:00 (2)
Complete: 🔍
Cache ID: 216::103

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

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Might our Artificial Intelligence support you?

Check our Alexa App!