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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.
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8 events from the most recent confirmed update back to the earliest known activity.
The Canadian Centre for Cyber Security published alert AV26-644 highlighting a Mozilla advisory for a vulnerability affecting Firefox versions prior to 152.0.4. The notice urged users and administrators to review Mozilla’s advisory and apply the necessary updates.
HKCERT published a security bulletin on multiple vulnerabilities affecting Mozilla products. The bulletin represents a separate regional advisory urging awareness and likely remediation based on Mozilla's disclosed fixes.
Debian published security advisory DSA 6350-1 announcing a security update for firefox-esr. This is a separate vendor response distributing fixes for Debian users following Mozilla's Firefox ESR vulnerability disclosures.
The Canadian Centre for Cyber Security published alert AV26-604 highlighting Mozilla advisories for Firefox, Firefox for iOS, and Firefox ESR, and urged users and administrators to review the advisories and apply updates.
Mozilla published MFSA 2026-57 covering multiple vulnerabilities fixed in Firefox 152 and Thunderbird 152, including issues that could enable remote code execution and sandbox escape. The advisory states fixes were also available in Firefox ESR 140.12 and Firefox ESR 115.37, and urged users to update.
Mozilla published MFSA 2026-58 covering security vulnerabilities fixed in Firefox ESR 140.12. The advisory documents security fixes for that ESR release.
Mozilla published MFSA 2026-59 covering security vulnerabilities fixed in Firefox ESR 115.37. The advisory documents security fixes for the ESR release.
Mozilla published MFSA 2026-56 covering security vulnerabilities fixed in Firefox for iOS 152.0.
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Mozilla released security advisories addressing vulnerabilities in **Firefox** and **Firefox ESR**, prompting the Canadian Centre for Cyber Security to urge organizations and users to apply updates. The affected versions included Firefox releases prior to `149`, Firefox ESR releases prior to `115.34`, and Firefox ESR releases prior to `140.9`, according to the earlier advisory. A subsequent Mozilla advisory issued additional fixes for the same product lines, affecting Firefox versions prior to `149.0.2`, Firefox ESR versions prior to `115.34.1`, and Firefox ESR versions prior to `140.9.1`. The Canadian Centre for Cyber Security described the notices as vendor patch and mitigation guidance and advised administrators to review Mozilla’s bulletins and deploy the necessary updates across exposed systems.
Jun 29, 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
Debian issued **DSA-6148-1** to ship a *firefox-esr* security update after Mozilla disclosed numerous vulnerabilities that could enable **arbitrary code execution**, **sandbox escape**, **same-origin policy bypass**, **information disclosure**, and **privilege escalation**. The advisory lists a large set of CVEs (including `CVE-2026-2757` through `CVE-2026-2793`, with gaps) and states fixes are available for Debian *oldstable* (bookworm) in **`firefox-esr` 140.8.0esr-1~deb12u1** (with the notice indicating corresponding updates for *stable* as well). The Canadian Centre for Cyber Security published **AV26-160**, relaying Mozilla’s February 24, 2026 advisories and urging organizations to apply updates for affected Mozilla products, including **Firefox ESR prior to 140.8**, **Firefox ESR prior to 115.33**, and **Firefox prior to 148**. The alert points administrators to Mozilla Foundation Security Advisories **2026-13**, **2026-14**, and **2026-15** as upstream references for the addressed vulnerabilities and remediation guidance.
Jun 29, 2026