CVE-2026-100821: Vulnerability in Mozilla Firefox
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.
AI Analysis
Technical Summary
This vulnerability involves a site isolation flaw within the Panning and Zooming component of Mozilla Firefox. Site isolation is a security feature designed to separate web content from different origins into different processes to prevent data leakage and cross-site attacks. The flaw could potentially undermine this isolation. Mozilla fixed this vulnerability in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The vendor advisory categorizes the impact as high but does not provide further technical details or exploitation methods.
Potential Impact
The vulnerability affects the security boundary enforcement of site isolation in Firefox's Panning and Zooming component, potentially allowing unauthorized access or data leakage between sites. The impact is rated high by Mozilla, indicating a significant security risk if exploited. However, there are no known exploits in the wild at this time.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. Users and administrators should update to these versions or later to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.
CVE-2026-100821: Vulnerability in Mozilla Firefox
Description
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.
Affected software
Mozilla
Firefox
pkg:github/mozilla/firefoxRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability involves a site isolation flaw within the Panning and Zooming component of Mozilla Firefox. Site isolation is a security feature designed to separate web content from different origins into different processes to prevent data leakage and cross-site attacks. The flaw could potentially undermine this isolation. Mozilla fixed this vulnerability in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. The vendor advisory categorizes the impact as high but does not provide further technical details or exploitation methods.
Potential Impact
The vulnerability affects the security boundary enforcement of site isolation in Firefox's Panning and Zooming component, potentially allowing unauthorized access or data leakage between sites. The impact is rated high by Mozilla, indicating a significant security risk if exploited. However, there are no known exploits in the wild at this time.
Mitigation Recommendations
Mozilla has released official fixes for this vulnerability in Firefox ESR 153.4, Firefox 157, Firefox ESR 115.42, and Firefox ESR 140.17. Users and administrators should update to these versions or later to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2026-09-26T19:18:35.743Z
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2026-100/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-97/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-98/","vendor":"Mozilla"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-99/","vendor":"Mozilla"}]
Threat ID: 6abbb3f7f7a7c541066409c1
Added to database: 09/29/2026, 12:49:59 UTC
Last enriched: 09/29/2026, 13:03:21 UTC
Last updated: 09/29/2026, 18:00:32 UTC
Views: 8
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