Loading story…
Mozilla has extended support for the Firefox 115 Extended Support Release (ESR) branch through March 2027, keeping security and maintenance updates available for users on older platforms that no longer support newer mainstream Firefox releases. The extension applies to systems including Windows 7, Windows 8.1, and macOS 10.12–10.14, allowing organizations and individuals on legacy endpoints to remain on a supported browser branch longer.
Mozilla cited continued usage on unsupported operating systems as a factor in the decision, with company statistics indicating that 4.796% of Firefox users were still running Windows 7 as of July 10, 2026. The move preserves a supported browser option for environments that have not yet migrated off aging operating systems, while the broader Firefox release train continues beyond the 115 ESR line.
Map this exposure pattern across your cloud, code, and identities.
2 events from the most recent confirmed update back to the earliest known activity.
Mozilla statistics cited in the coverage stated that 4.796% of Firefox users were still using Windows 7. The figure was explicitly anchored as of July 10, 2026.
Mozilla extended support for the Firefox 115 Extended Support Release branch until March 2027 so users on unsupported older operating systems can continue receiving updates. The extension applies to systems including Windows 7, Windows 8.1, and macOS 10.12 through 10.14.
Vulnerabilities, threat actors, malware, products, organizations, and breaches Mallory has linked to this story.
See where this exposure pattern shows up across your cloud, code, supply chain, and non-human identities.
4 references tracked. Mallory keeps watching after this page renders.
opennet.me
Open sourceopennet.ru
Open sourcewhattrainisitnow.com
Open sourcesupport.mozilla.org
Open sourceMap indicators from this story to your assets and identify affected systems in minutes.
Every observed campaign, victim, and pivot linked to actors named in this story.
Malware, exploits, and IOCs connected to the activity described here.
YARA, Sigma, and Snort rules deployed to your SIEM as soon as they’re published.
Get matching new stories delivered to your team as they break — not the next morning.
Ask questions about this story and take action on the answers.
Other stories Mallory is tracking that overlap on entities, sources, or topic labels.
Mozilla released **Firefox 156** and **Firefox ESR 153.3** to address security vulnerabilities in its browser products. The Canadian Centre for Cyber Security advisory `AV26-924` identifies Firefox versions earlier than 156 and Firefox ESR versions earlier than **115.41**, **140.16**, and **153.3** as affected. Organizations should update standard Firefox deployments to version 156 and move ESR deployments to the applicable fixed release—115.41, 140.16, or 153.3. Administrators should review Mozilla’s associated security advisories, including `MFSA-2026-90` and `MFSA-2026-93`, and prioritize remediation across managed endpoints.
Sep 22, 2026
Mozilla released **critical security updates** for Firefox and Firefox ESR, and the Canadian Centre for Cyber Security urged organizations and users to apply them promptly. The affected versions are **Firefox prior to 153**, **Firefox ESR prior to 140.13**, and **Firefox ESR prior to 115.38**. The advisories were issued as patch guidance rather than a confirmed report of active exploitation, but they address vulnerabilities serious enough to warrant immediate attention. Reporting on the release says Firefox 153 and the updated ESR branches include a broad set of fixes, with one source citing **216 vulnerabilities** resolved. The update also addresses flaws tracked as **`CVE-2026-16411`** and **`CVE-2026-16360`**, alongside multiple memory-safety issues described as potentially exploitable for **arbitrary code execution**. In addition to security remediation, the browser release includes privacy and isolation improvements such as stronger local network access protections and changes to cookie handling behavior.
Jul 21, 2026
Mozilla released security updates to address vulnerabilities in multiple Firefox products, including **Firefox 152**, **Firefox for iOS 152.0**, **Firefox ESR 140.12**, and **Firefox ESR 115.37**. The fixes were published through Mozilla Foundation Security Advisories **`MFSA 2026-56`** through **`MFSA 2026-59`**, with the Firefox for iOS update specifically covered in **`MFSA 2026-56`**. The Canadian Centre for Cyber Security issued alert **`AV26-604`** highlighting the advisories and warning that systems running versions prior to those releases remain affected. The agency urged users and administrators to review Mozilla’s guidance and apply the updates needed to remediate the disclosed flaws across supported desktop, mobile, and extended support browser versions.
Jun 30, 2026